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Researchers Submit Patent Application, "Organic Light Emitting Device and Manufacturing Method Thereof", for Approval

May 29, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors Choi, Jin-Baek (Yongin-City, KR); Choung, Ji-Young (Yongin-City, KR); Lee, Joon-Gu (Yongin-City, KR); Lee, Yeon-Hwa (Yongin-City, KR); Kim, Won-Jong (Yongin-City, KR); Bang, Hyun-Sung (Yongin-City, KR), filed on March 12, 2013, was made available online on May 15, 2014.

The patent's assignee is Samsung Display Co., Ltd.

News editors obtained the following quote from the background information supplied by the inventors: "The present disclosure relates to an organic light emitting device and a manufacturing method of the organic light emitting device and more particularly, to an organic light emitting device in which a conductive capping layer is laminated on a cathode and a manufacturing method of the organic light emitting device.

"An organic light emitting device (OLED) has utility as an image display medium because of a high response speed, low power consumption, and a wide viewing angle according to a self emission mode. Further, since the organic light emitting device may be manufactured through simple processes at a relatively low temperature, the organic light emitting device has received attention as a next-generation flat panel display device.

"In general, an organic light emitting device may have a structure in which an anode and a cathode are sequentially placed on a flat insulating layer which covers a thin film transistor provided on a substrate, and an organic layer is interposed between the anode and the cathode.

"During operation of an organic light emitting device holes supplied from the anode and electrons supplied from the cathode are coupled with each other in an organic layer formed between the anode and the cathode to form excitons having high energy where when the excitons fall down to lower energy, light is generated.

"An organic light emitting device may be a rear emission or front emission type organic light emitting device according to a direction in which the light generated in the organic layer is emitted outside the device.

"The rear emission type organic light emitting device is a mode in which light is emitted in the anode direction by using a transparent anode and a reflective cathode. In a rear emission type organic light emitting device there can be a problem in that a light emission area is reduced by an area occupied by a thin film transistor circuit disposed on the substrate.

"As a method of solving the problem, a front emission type organic light emitting device which emits light in the cathode direction by using a reflective anode and a transflective cathode has been suggested.

"A front emission type organic light emitting device may include a metal layer as a cathode. However, the metal layer which may be used as the cathode may need to be formed at a predetermined thickness in order to make the cathode into the transflective type, and as a result, there is a problem in that sheet resistance of the cathode is largely increased and thus power consumption is increased."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "Some embodiments provide an organic light emitting device capable of reducing sheet resistance while maintaining an optical characteristic by laminating a conductive capping layer on a cathode and a manufacturing method thereof.

"An exemplary embodiment of the present disclosure provides an organic light emitting device, including: a substrate; a first electrode on the substrate; an emission layer on the first electrode: a second electrode on the emission layer; and a conductive capping layer on the second electrode.

"In some embodiments, the conductive capping layer may be formed with a single layer or multilayer.

"In some embodiments, the second electrode may be formed as a transmissive electrode by using at least one of Mg:Ag, LiF:Al, Li:Al, Li, Ca, Ag, and Al.

"In some embodiments, the conductive capping layer may contain indium oxide.

"In some embodiments, the indium oxide may have a composition of represented by the formula InO.sub.x, and an x value may be 1.3 or more to less than 1.5.

"In some embodiments, a thickness of the conductive capping layer may be 300 .ANG. to 2,000 .ANG.

"In some embodiments, a refractive index of the conductive capping layer may be 1.7 to 2.3.

"Some embodiments provide a manufacturing method of an organic light emitting device, including: forming a first electrode on a substrate; forming an emission layer on the first electrode; forming a second electrode on the emission layer; and forming a conductive capping layer on the second electrode.

"In some embodiments, the forming of the second electrode may include forming a transmissive electrode by using at least one of Mg:Ag, LiF:Al, Li:Al, Li, Ca, Ag, and Al as a material.

"In some embodiments, the forming of the conductive capping layer may use indium oxide as a material, and an x value of the indium oxide may be 1.3 or more to less than 1.5.

"In some embodiments, the forming of the conductive capping layer may include controlling a thickness of the conductive capping layer to be 300 .ANG. to 2,000 .ANG.

"In some embodiments, the forming of the conductive capping layer may use any one method of an ion beam deposition process, a spin coating process, a printing process, a sputtering process, a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process, a plasma enhanced chemical vapor deposition (PECVD) process, a high density plasma-chemical vapor deposition (HDP-CVD) process, and a vacuum deposition process.

"In some embodiments, the forming of the conductive capping layer may use an ion beam associated deposition process.

"In some embodiments, ions injected during the ion beam associated deposition (IBAD) process may include argon (Ar) and oxygen (O.sub.2).

"In some embodiments, an injection velocity of argon (Ar) injected during the ion beam associated deposition (IBAD) process may be 5 to 30 cm.sup.2/min.

"In some embodiments, an injection velocity of oxygen (O.sub.2) injected during the ion beam associated deposition (IBAD) process may be 3 to 40 cm.sup.2/min.

"According to some embodiments of the present disclosure, conductivity of a cathode becomes excellent by forming a conductive capping layer on the cathode made of transmissive metal to reduce sheet resistance, and as a result, power consumption of an organic light emitting device may be improved.

"In some embodiments, the organic light emitting device may have a high transmission property by forming the conductive capping layer with indium oxide having a constant ratio of oxygen and indium to protect the organic light emitting device from external moisture and oxygen. Further, since the conductive capping layer made of indium oxide is amorphous, surface roughness is excellent and thus light extraction efficiency may be improved. In some embodiments, the indium oxide may have a composition of represented by the formula InO.sub.x, and an x value may be 1.3 or more to less than 1.5.

"In some embodiments, light lost by total reflection is emitted outside by forming the conductive capping layer at a predetermined refractive index or more, and as a result, light extraction efficiency may be improved.

"The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

"FIG. 1 is a cross-sectional view for describing an organic light emitting device according to an exemplary embodiment of the present disclosure.

"FIGS. 2A to 2E are diagrams for describing a manufacturing method of the organic light emitting device according to the exemplary embodiment of the present disclosure.

"FIG. 3A is a diagram illustrating a surface state of indium oxide according to the exemplary embodiment of the present disclosure, and FIG. 3B is a diagram illustrating a surface state of ITO for comparing the surface state of indium oxide. In some embodiments, the indium oxide may have a composition of represented by the formula InO.sub.x, and an x value may be 1.3 or more to less than 1.5."

For additional information on this patent application, see: Choi, Jin-Baek; Choung, Ji-Young; Lee, Joon-Gu; Lee, Yeon-Hwa; Kim, Won-Jong; Bang, Hyun-Sung. Organic Light Emitting Device and Manufacturing Method Thereof. Filed March 12, 2013 and posted May 15, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=5004&p=101&f=G&l=50&d=PG01&S1=20140508.PD.&OS=PD/20140508&RS=PD/20140508

Keywords for this news article include: Indium, Chalcogens, Heavy Metals, Nanotechnology, Emerging Technologies, Samsung Display Co. Ltd, Chemical Vapor Deposition.

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Source: Politics & Government Week


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