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Researchers Submit Patent Application, "One-Way Transparent Display", for Approval

May 15, 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 inventor Hack, Michael (Princeton, NJ), filed on October 19, 2012, was made available online on May 1, 2014.

No assignee for this patent application has been made.

News editors obtained the following quote from the background information supplied by the inventors: "Opto-electronic devices that make use of organic materials are becoming increasingly desirable for a number of reasons. Many of the materials used to make such devices are relatively inexpensive, so organic opto-electronic devices have the potential for cost advantages over inorganic devices. In addition, the inherent properties of organic materials, such as their flexibility, may make them well suited for particular applications such as fabrication on a flexible substrate. Examples of organic opto-electronic devices include organic light emitting devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors. For OLEDs, the organic materials may have performance advantages over conventional materials. For example, the wavelength at which an organic emissive layer emits light may generally be readily tuned with appropriate dopants.

"OLEDs make use of thin organic films that emit light when voltage is applied across the device. OLEDs are becoming an increasingly interesting technology for use in applications such as flat panel displays, illumination, and backlighting. Several OLED materials and configurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and 5,707,745, which are incorporated herein by reference in their entirety.

"One application for phosphorescent emissive molecules is a full color display. Industry standards for such a display call for pixels adapted to emit particular colors, referred to as 'saturated' colors. In particular, these standards call for saturated red, green, and blue pixels. Color may be measured using CIE coordinates, which are well known to the art.

"One example of a green emissive molecule is tris(2-phenylpyridine) iridium, denoted Ir(ppy)3, which has the following structure:

"##STR00001##

"In this, and later figures herein, we depict the dative bond from nitrogen to metal (here, Ir) as a straight line.

"As used herein, the term 'organic' includes polymeric materials as well as small molecule organic materials that may be used to fabricate organic opto-electronic devices. 'Small molecule' refers to any organic material that is not a polymer, and 'small molecules' may actually be quite large. Small molecules may include repeat units in some circumstances. For example, using a long chain alkyl group as a substituent does not remove a molecule from the 'small molecule' class. Small molecules may also be incorporated into polymers, for example as a pendent group on a polymer backbone or as a part of the backbone. Small molecules may also serve as the core moiety of a dendrimer, which consists of a series of chemical shells built on the core moiety. The core moiety of a dendrimer may be a fluorescent or phosphorescent small molecule emitter. A dendrimer may be a 'small molecule,' and it is believed that all dendrimers currently used in the field of OLEDs are small molecules.

"As used herein, 'top' means furthest away from the substrate, while 'bottom' means closest to the substrate. Where a first layer is described as 'disposed over' a second layer, the first layer is disposed further away from substrate. There may be other layers between the first and second layer, unless it is specified that the first layer is 'in contact with' the second layer. For example, a cathode may be described as 'disposed over' an anode, even though there are various organic layers in between.

"As used herein, 'solution processible' means capable of being dissolved, dispersed, or transported in and/or deposited from a liquid medium, either in solution or suspension form.

"A ligand may be referred to as 'photoactive' when it is believed that the ligand directly contributes to the photoactive properties of an emissive material. A ligand may be referred to as 'ancillary' when it is believed that the ligand does not contribute to the photoactive properties of an emissive material, although an ancillary ligand may alter the properties of a photoactive ligand.

"As used herein, and as would be generally understood by one skilled in the art, a first 'Highest Occupied Molecular Orbital' (HOMO) or 'Lowest Unoccupied Molecular Orbital' (LUMO) energy level is 'greater than' or 'higher than' a second HOMO or LUMO energy level if the first energy level is closer to the vacuum energy level. Since ionization potentials (IP) are measured as a negative energy relative to a vacuum level, a higher HOMO energy level corresponds to an IP having a smaller absolute value (an IP that is less negative). Similarly, a higher LUMO energy level corresponds to an electron affinity (EA) having a smaller absolute value (an EA that is less negative). On a conventional energy level diagram, with the vacuum level at the top, the LUMO energy level of a material is higher than the HOMO energy level of the same material. A 'higher' HOMO or LUMO energy level appears closer to the top of such a diagram than a 'lower' HOMO or LUMO energy level.

"As used herein, and as would be generally understood by one skilled in the art, a first work function is 'greater than' or 'higher than' a second work function if the first work function has a higher absolute value. Because work functions are generally measured as negative numbers relative to vacuum level, this means that a 'higher' work function is more negative. On a conventional energy level diagram, with the vacuum level at the top, a 'higher' work function is illustrated as further away from the vacuum level in the downward direction. Thus, the definitions of HOMO and LUMO energy levels follow a different convention than work functions.

"More details on OLEDs, and the definitions described above, can be found in U.S. Pat. No. 7,279,704, which is incorporated herein by reference in its entirety."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventor's summary information for this patent application: "OLED devices and method of fabricating the same are provided. The devices include emissive regions and locally-transparent regions, such that the device has an overall transparency of at least 5%.

"In an embodiment of the invention disclosed herein, a device may include a light emitting surface a first region and a second region, where the device transmits light through the first region and emits light from the second region, and has an overall device transparency of at least 5%, at least 10%, or more. The device may be, for example, a display such as a full-color display, an OLED display, an AMOLED display, a flexible OLED display, or the like. The second region may have a higher local transparency than the first region, for example where the local transparency of the region is less than 5%, less than 1%, or less. The device may include multiple OLEDs configured to emit light through the first surface, which may be arranged to emit light only or primarily through the first region of the light emitting surface. The OLEDs may occupy not more than about 75% of the total area of the display. At least 70% of the area of the display not occupied by the plurality of OLEDs may have a local transparency of at least 25%, 50%, or more. The device may be divided into regions, each of which includes at least one OLED and a transparent region having a local transparency of at least 25%. Overall, such transparent regions may occupy at least 25% of the total area of the light emitting surface. In some configurations the OLED devices may include a white emitting device and/or one or more color filters. The device may be flexible, and may be fabricated on, for example, a plastic substrate. It also may include additional layers, such as protective layers, including a single layer barrier encapsulation layer, which may be disposed over the light emitting surface or another surface of the device.

"In an embodiment of the invention disclosed herein, an OLED device may include two electrodes having different surface areas, where the surface area of one is not more than about 80% of the surface area of the other, and an emissive layer disposed between the electrodes. The OLED device may be configured to emit light only through one electrode. Alternatively or in addition, multiple electrodes may be disposed on one side of the emissive layer, which have a combined surface area of not more than about 80% of the surface area of the other electrode. The device may have an overall transparency of at least 5%, 10%, or more. It may include an OLED, an AMOLED, a flexible OLED, one or more color filters or filter layers, a flexible substrate such as a plastic substrate, a protective layer such as a single layer barrier encapsulation, or the like.

"In an embodiment of the invention, a method of fabricating a device as disclosed herein is provided. The method may include, for example, depositing an anode material over a substrate having a transparency of at least 5%, to form a patterned layer that covers a first portion of the substrate and does not cover a second portion of the substrate, depositing an emissive layer over the first portion and the second portion of the substrate, and depositing a cathode material over the first portion and the second portion of the substrate. Such a method also may use appropriate substrates, emissive layers, control components, and other components as disclosed herein. The resulting device may have an overall transparency of 5%, 10%, or more.

BRIEF DESCRIPTION OF THE DRAWINGS

"FIG. 1 shows an organic light emitting device.

"FIG. 2 shows an inverted organic light emitting device that does not have a separate electron transport layer.

"FIG. 3 shows a schematic top view of a region of an example device according to an embodiment of the invention.

"FIG. 4A shows an example arrangement of emissive and transparent regions according to an embodiment of the invention, in which the emissive regions have non-equal areas the transparent region is contiguous.

"FIG. 4B shows an example arrangement of emissive and transparent regions according to an embodiment of the invention, in which the transparent region is non-contiguous.

"FIG. 4C shows an example arrangement of emissive and transparent regions according to an embodiment of the invention that includes two emissive regions separated by a transparent region.

"FIG. 4D shows an example arrangement of emissive and transparent regions according to an embodiment of the invention that includes a non-contiguous transparent region and emissive regions with non-equal areas.

"FIG. 5 shows an example device according to an embodiment of the invention that includes multiple emissive regions and a transparent region that surrounds the emissive regions.

"FIG. 6 shows an example of a device according to an embodiment of the invention that includes two electrodes, where one has a surface area less than the surface area of the other.

"FIG. 7 shows an example of a device according to an embodiment of the invention that includes multiple electrodes, where the combined electrode surface area on one side of the device is less than the surface area of a single electrode on the other side of the device.

"FIG. 8 shows an example device according to an embodiment of the invention in which an emissive layer is disposed over a non-transparent electrode."

For additional information on this patent application, see: Hack, Michael. One-Way Transparent Display. Filed October 19, 2012 and posted May 1, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=5071&p=102&f=G&l=50&d=PG01&S1=20140424.PD.&OS=PD/20140424&RS=PD/20140424

Keywords for this news article include: Patents.

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Source: Politics & Government Week


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