News Column

"Non-Crystalline Inorganic Light Emitting Diode" in Patent Application Approval Process

July 16, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- A patent application by the inventors Mohammed, Ilyas (Santa Clara, CA); Wang, Liang (Milpitas, CA), filed on December 21, 2012, was made available online on July 3, 2014, according to news reporting originating from Washington, D.C., by VerticalNews correspondents.

This patent application is assigned to Invensas Corporation.

The following quote was obtained by the news editors from the background information supplied by the inventors: "Light emitting diodes (LEDs) are gaining wide acceptance in a variety of area-illumination applications, for example, architectural lighting, residential illumination, industrial lighting, outdoor lighting, theatrical lighting and the like. Crystalline inorganic LEDs based on Gallium nitride (GaN) are a common type of LEDs utilized in such applications.

"In comparison to conventional organic light emitting diodes (OLEDs), crystalline inorganic LEDs offer a number of advantages, including superior brightness, e.g., brightness in the range of 6900 klm/m.sup.2 for LED in comparison to about 10 klm/m.sup.2 for OLED, increased efficiency, e.g., 144 lm/W for LED in comparison to 60 lm/W for OLED, advantageous lifetime, e.g., 50,000 hours for LEDs versus 10,000 hours for a blue OLED, and a beneficially increased current density, e.g., 35 A/cm.sup.2 for an LED in comparison to about 10 mA/cm.sup.2 for an OLED.

"However, organic light emitting diodes have some advantages in comparison to inorganic crystalline light emitting diodes. Organic LEDs may be constructed as an area light source, whereas crystalline inorganic LEDs are generally point sources, often rendering such LEDs unsuitable for, or requiring complex optics for, area lighting applications. In addition, crystalline inorganic LEDs generally require an epitaxial growth process, which is generally considered an expensive process, e.g., requiring high vacuum and long durations. Further, crystalline inorganic LEDs often require a lattice-matched single crystal substrate, e.g., sapphire or Silicon carbide, which are generally more expensive than other substrates, and may often have less desirable optical and/or thermal properties. Still further, even a slight mismatch in a crystal lattice or in a coefficient of thermal expansion (CTE) between a substrate and an epitaxial layer grown at high temperature may result in interfacial defects, dislocations and/or cracks, which may significantly lower the production yield. In contrast, organic LEDs are generally amorphous, do not require epitaxial growth and offer greater variety of substrate selection, lower material and manufacturing costs, and higher manufacturing throughput and yield."

In addition to the background information obtained for this patent application, VerticalNews journalists also obtained the inventors' summary information for this patent application: "Therefore, what is needed are systems and methods for non-crystalline inorganic light emitting diodes. What is additionally needed are systems and methods for non-crystalline inorganic light emitting diodes that do not require epitaxial manufacturing processes, such as chemical vapor deposition (CVD) or molecular beam epitaxy (MBE). A further need exists for systems and methods for non-crystalline inorganic light emitting diodes that are compatible and complementary with existing systems and methods of integrated circuit design, manufacturing and test. Embodiments of the present invention provide these advantages.

"In accordance with a first embodiment of the present invention, an article of manufacture includes a light emitting diode. The light emitting diode includes a non-crystalline inorganic light emission layer and first and second semiconducting non-crystalline inorganic charge transport layers surrounding the light emission layer. The light emission layer may be amorphous. The charge transport layers may be configured to inject one type of charge carrier and block the other type of charge carrier.

"In accordance with another embodiment of the present invention, an article of manufacture includes a light emitting diode. The light emitting diode includes a first non-crystalline inorganic layer configured for transporting holes and blocking electrons and having a hole conduction band and a hole valence band. The light emitting diode also includes a second non-crystalline inorganic layer, disposed on the first layer, configured for emitting light and having an emission conduction band and a emission valence band. The light emitting diode further includes a third non-crystalline inorganic layer, disposed on the second layer, configured for transporting electrons and blocking holes and having an electron conduction band and an electron valence band. The alignment of the hole, emission and electron conduction bands and the hole, emission and electron valence bands favor both charge injection and charge confinement.

"In accordance with a further embodiment of the present invention, an article of manufacture includes a light emitting device. The light emitting device includes a first diode unit including a first non-crystalline inorganic light emission layer configured to emit light of a first wavelength and first and second non-crystalline inorganic charge transport layers surrounding the first light emission layer. The light emitting device includes a second diode unit including a second non-crystalline inorganic light emission layer configured to emit light of a second wavelength and third and fourth non-crystalline inorganic charge transport layers surrounding the second light emission layer.

"The light emitting device includes a non-crystalline inorganic charge generation layer between the first and second diode units. An anode terminal of the first diode unit is coupled to a cathode terminal of the second anode unit, and the first and second diode units and the charge generation layer form a single stack of materials. The first and second wavelengths may be substantially the same or different. The light emitting device may be configured to produce white light.

"In accordance with a method embodiment of the present invention, a non-crystalline anode material is deposited on a non-crystalline substrate. A first non-crystalline charge transport material is deposited on the anode material. The first charge transport material includes a semiconductor material. Non-crystalline light emitting material is deposited on the charge transport material. A second non-crystalline charge transport material is deposited on the light emitting material. The second charge transport material includes a semiconductor. Non-crystalline cathode material is deposited on the second charge transport material, to form a light emitting diode. The light emitting diode may be annealed.

BRIEF DESCRIPTION OF THE DRAWINGS

"The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. Unless otherwise noted, the drawings are not drawn to scale.

"FIG. 1A illustrates an energy band alignment for a crystalline inorganic light emitting diode in accordance with the conventional art.

"FIG. 1B illustrates an energy band alignment for a non-crystalline inorganic light emitting diode in accordance with embodiments of the present invention.

"FIG. 2 illustrates a side sectional view of a non-crystalline inorganic light emitting diode, in accordance with embodiments of the present invention.

"FIG. 3 illustrates a side sectional view of a non-crystalline inorganic light emitting diode, in accordance with embodiments of the present invention.

"FIG. 4 illustrates a method of manufacturing a non-crystallite inorganic light emitting diode, in accordance with embodiments of the present invention.

"FIG. 5 illustrates a stacking structure for a non-crystalline inorganic multiple emitter light emitting diode.

"FIG. 6 illustrates an example of an application of a light emitting diode, in accordance with embodiments of the present invention.

"FIG. 7 illustrates an exploded view of a panel form of a non-crystalline inorganic light emitting diode, in accordance with embodiments of the present invention."

URL and more information on this patent application, see: Mohammed, Ilyas; Wang, Liang. Non-Crystalline Inorganic Light Emitting Diode. Filed December 21, 2012 and posted July 3, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=6597&p=132&f=G&l=50&d=PG01&S1=20140626.PD.&OS=PD/20140626&RS=PD/20140626

Keywords for this news article include: Electronics, Semiconductor, Invensas Corporation, Light-emitting Diode.

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Source: Electronics Newsweekly


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