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Electroluminescent devices with improved optical out-coupling efficiencies

a technology of optical out-coupling efficiency and electroluminescent devices, which is applied in the direction of basic electric elements, semiconductor devices, electrical equipment, etc., can solve the problems of limited optical out-coupling efficiency of oleds

Inactive Publication Date: 2016-09-15
NAT TAIWAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The patent describes a new electroluminescent device that includes a special structure designed to improve the amount of light that is emitted and directed out of the device. This structure includes layers of material that help to reduce the amount of light that is reflected and lost during the process. The results are a more efficient device that produces brighter light and directs it in a better way. This may be useful for a variety of applications, such as in display screens or lighting.

Problems solved by technology

However, in typical OLED structures, optical out-coupling efficiencies of OLEDs are still limited.
Therefore, in typical top-emitting OLED structures, optical out-coupling efficiencies are generally also limited.

Method used

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  • Electroluminescent devices with improved optical out-coupling efficiencies
  • Electroluminescent devices with improved optical out-coupling efficiencies
  • Electroluminescent devices with improved optical out-coupling efficiencies

Examples

Experimental program
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Effect test

embodiment 1

[0093] structure and fabrication method for the electroluminescent device having the optically reflective concave structure.

[0094]FIGS. 13a, 13b and 13c illustrate several possible embodiments of OLEDs having the concave and optically reflective structure 200, including the structure with the OLED emission zone 305 within the concave area (at the bottom), as shown in FIG. 13a, and the structure with the OLED emission zone 305b extending to the side slopes and the top edge of the concave area, as shown in FIGS. 13b and 13c. In all these OLED structures, the concave and optically reflective structures 200 are first formed on a substrate 100. Then, various functional layers 300 of the OLED, such as emission layer(s), charge transport layer(s), electrode layer(s), insulating dielectric layer(s) 301 to define the emission area of the OLED, and passivation / capping layer(s) 310 etc. that typically have refractive indices higher than that of air, are disposed over surface of the concave and...

embodiment 2

[0117] structure and fabrication method for the electroluminescent device having the optically reflective concave structure with the flat or curved exposed surface of the index-matching material.

[0118]FIGS. 17a, 17b and 17c illustrate several other possible embodiments of OLEDs having the concave and optically reflective structure 200, including the structure with the OLED emission zone 305 within the concave area in FIG. 17a and the structure with the OLED emission zone 305b extending to the top edge of the concave area in FIGS. 17b and 17c. Their structures and possible fabrication are similar to those shown in FIGS. 13a, 13b and 13c and FIG. 14, and yet a relatively transparent material 400 (referred as the index-matching filling material) having a refractive index similar to those of the OLED emission layer(s) / emission zone 305 / 305b is further disposed over the OLED functional layers 300 within the concave area to fill or nearly fill the concave and optically reflective structur...

embodiment example 3

[0130] top-emitting active matrix OLED display (top-emitting AMOLED) having the optically reflective concave structure.

[0131]FIG. 19 shows the schematic integration structure for the pixel of a top-emitting AMOLED. It has a pixel definition layer-PDL P (or planarization & interlayer) of an appropriate thickness, which has tapered opening for defining the pixel OLED emission area and also serves to planarize surface corrugation caused by TFTs / electrode bus lines / interconnection / other structures of the backplane below.

[0132]FIG. 19 shows that there is a concave structure in the AMOLED pixel OLED structure. By using such a concave structure in the AMOLED pixel OLED structure, by forming patterned reflective electrode E over the surface of the concave structure, and by making its electrical contact to the TFT interconnection 500 beneath, OLED pixels having the concave and optically reflective structure can be formed. By adding one or two more photo-mask processing steps in the AMOLED fa...

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Abstract

An electroluminescent (EL) device is disclosed. An optically reflective concave structure includes a first surface and a second surface that lies at an angle relative to the first surface, wherein at least the first and second surfaces are optically reflective. One or more functional layers include a light emitting layer, disposed over the surfaces of the optically reflective concave structure, wherein at least one electroluminescent area of the light emitting layer is defined on the first surface. Especially, the ratio between the width of the first surface and the thickness of the one or more functional layers in the optically reflective concave structure is smaller than a constant value.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 62 / 177,273, filed on Mar. 11, 2015, and entitled “Organic Light-Emitting Device Structures with Improved Optical Out-Coupling and Their Applications”, the disclosure of which is incorporated by reference in its entirety.FIELD OF THE INVENTION[0002]The present invention pertains to an electroluminescent (EL) device, and more particularly pertains to an organic light-emitting device (OLED) structures with improved optical out-coupling and their applications.BACKGROUND OF THE INVENTION[0003]Due to various merits of organic light-emitting devices (OLEDs), such as high efficiency, wide viewing angles, fast response, potentially low cost etc., OLED technologies have become an important next-generation display technology since Dr. Tang and VanSlyke reported the first efficient and practical OLED in 1987. Due to increasing efficiencies, the OLED is ...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): H01L51/52H01L27/32
CPCH01L51/5275H01L51/5271H01L27/3276H01L51/5265H01L51/5268H10K59/877H10K59/879H10K59/80H10K59/122H10K2102/351H01L33/60H10K50/856H10K59/00H10K50/854
Inventor WU, CHUNG-CHIHLIN, CHUN-YULEE, WEI-KAIJIAO, MINLIN, HOANG YANSU, GUO-DONG
Owner NAT TAIWAN UNIV