Patent Application
20130248914
The present invention relates, generally, to the field of optoelectronic devices, and, specifically, to the field of packaged optoelectronic devices and methods for manufacturing.
Optoelectronic devices generally include a wide array of devices that include light emitting devices used in display systems or photovoltaic devices used in energy generation systems. Optoelectronic devices are structured to include an active layer disposed between two electrodes. In light emitting devices, when a power source connected between the two electrodes supplies electric energy to the two electrodes, current flows through the active layer and causes the active layer to emit light. On the other hand, in photovoltaic devices the active layer absorbs energy from light and converts this energy into electric energy. The electric energy can be fed to a load by connecting the load between the two electrodes of the photovoltaic device.
Manufacturing of optoelectronics devices includes approaches like vacuum deposition of semiconductor materials, usage of solution processed materials, and inkjet printing technology. In the vacuum deposition of semiconductor materials approach, a substrate made from non-conducting material like glass and plastic is used as a base and different layers of the optoelectronic device are deposited on the base. In inkjet printing technology, active layers are printed on a non-conducting substrate made from suitable materials.
Regardless of the construction of the device, it is necessary to pack the optoelectronic device in order to protect it from the deteriorating effects of moisture and oxygen exposure. While it is necessary to pack the optoelectronic device to keep moisture and oxygen away, it is also important to provide for mechanisms to connect the electrodes to a power source. Most Organic Light Emitting Diodes (OLEDs) provide for electrical connections through feed-through configuration. For an example, barrier films that are used for fabrication of OLEDs typically include a thin transparent oxide layer on a plastic film and provide electrical connections through electrical wires that sealed to the edges of the optoelectronic device with the help of conductive adhesives. However, with such a configuration, it has been observed that moisture and oxygen can permeate at the edges of the optoelectronic device. Further, intrinsic moisture in the adhesive can also permeate through the package and reach the active layers.
Thus, there is a need for an improved thin flexible packaging technology for low cost production of optoelectronic devices.
Briefly, in one aspect, the present invention relates to a packaged optoelectronic device. The packaged optoelectronic device includes at least one optoelectronic device with a cathode and an anode. The at least one optoelectronic device is sandwiched between a first and a second barrier layer. Further the second barrier layer includes at least one aperture. Furthermore, the packaged optoelectronic device includes a plurality of thin electrically conductive connectors. Each of the thin electrically conductive connectors is coupled to at least one of the anode and the cathode. Furthermore, the thin electrically conductive connectors extend out of the packaged optoelectronic device from the at least one aperture to be configured to be connected to an external power source to provide power to at least one of the anode and the cathode.
In another aspect, the present invention relates to a packaged optoelectronic device that includes at least one optoelectronic device and at least one conductive bus line. The at least one optoelectronic device includes a cathode and an anode and is sandwiched between a first and a second barrier layer. The second barrier layer includes at least one aperture. Further, the conductive bus line is electrically coupled with at least one of the cathode and anode. The conductive bus line extends out of the packaged optoelectronic device through the at least one aperture.
In yet another aspect, the present invention relates to a process for manufacturing a packaged optoelectronic device. The process includes sandwiching an optoelectronic device between a first and a second barrier layer. The sandwiched optoelectronic device includes at least one anode and at least one cathode. Further, the process includes forming at least one aperture in the second barrier layer. The process further includes the step of passing at least one thin electrically conductive connector through the at least one aperture. Furthermore, the process includes the step of electrically coupling the at least one thin electrically conductive connector with at least one of the anode and the cathode.
In yet another aspect, the present invention relates to a packaged optoelectronic device including a first transparent barrier layer; a second barrier layer with at least one aperture; at least one optoelectronic device sandwiched between the first and second barrier layers, the optoelectronic device comprising an anode, and a cathode; a plurality of thin electrically conductive connectors coupled to the anode and the cathode; and a plurality of conductive bus lines electrically coupled to the plurality of thin electrically conductive connectors and extending out from the at least one aperture.
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Reference will be made below in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals used throughout the drawings refer to the same or like parts.
Embodiments of the invention described herein relate to a packaged optoelectronic device. The packaged optoelectronic device includes an optoelectronic device that is sandwiched between two barrier layers. Examples of the optoelectronic device include, but are not limited to, photovoltaic devices and light emitting devices. The optoelectronic devices include two electrodes, a cathode and an anode, which when connected to a power source allow the devices to either emit light or provide energy to the power source. When the electrodes of a light emitting optoelectronic device are connected to the power source and are excited by the power source, light is emitted. This phenomenon is used in display systems for mobile phones, television sets etc. Whereas, when the light is incident on photovoltaic devices, it provides electric energy through the electrodes to the connected power source. The present invention provides for mechanisms to electrically couple the electrodes of the optoelectronic device to the power source outside the package without letting moisture ingression. In the present invention, at least one aperture is provided in one of the two barrier layers. At least one thin electrically conductive connector is coupled to the electrodes and extended out of the at least one aperture. The electrically conductive connector is connected to a power source outside the package.
The second barrier layer 150 includes a thin interface layer 122, a barrier layer 124, and optional insulating layer 126. Suitable materials for use as the second barrier layer 150 include commercially available multilayer packaging or lidding materials having moisture- and optionally oxygen-barrier properties in the form of films or sheets, especially heat-sealable materials. Lidding materials are typically composed of multiple thin polymer layers; lidding foils also include a metal foil, typically aluminum, sandwiched between polymer layers. One example of a suitable material for the second barrier layer 150 is Tolas TPC-0814B lidding foil, produced by Tolas Healthcare Packaging, Feasterville, Pa., a division of Oliver-Tolas, Grand Rapids, Mich.
The packaged optoelectronic device 100 is a single pixel device including only one optoelectronic device 140, but it is known in the art that individual pixels can be monolithically integrated in a series configuration (as illustrated in the top view of
It is also understood that a multi-pixel configuration of optoelectronic devices 140, 202, 204, and 206 can be formed by individually placing devices 140, 202, 204, and 206 between separate sheets of barrier layers 130 and 150. The individual packages thus formed are integrated to form a series configuration of single pixel optoelectronic devices. Further, multi-pixel optoelectronic device 200 can also be obtained by overlapping the optoelectronic devices 140, 202, 204, and 206 over each other to form a tile structure. The tile structure of the optoelectronic devices 140, 202, 204, and 206 is then sandwiched between the barrier layers 130 and 150 to form the packaged optoelectronic device 200.
According to one embodiment of the present invention, the electrically conductive connectors 302 and 308 are composed of foils of a conductive metal, such as aluminum. The connectors 302 and 308 are selected based on the size of the apertures 304 and 310 made in the second barrier layer 150. The connectors 302 and 308 are selected such that no space is left in the apertures 304 and 310 for moisture, oxygen, and/or vapors to enter the packaged optoelectronic device 200. According to certain embodiments, aluminum foils of thickness less than or equal to 20 microns are used to make the thin electrically conductive connectors 302 and 308. Although only two apertures 304 and 310 are shown, in some embodiments, the second barrier layer 150 includes multiple, that is, more than two, apertures.
The blocks 306 and 312 are formed from electrically conductive adhesive material placed by various means, including manual or automated means. An example of a suitable material for the blocks 306 and 312 is Staystik 571, available from Cookson Electronics, Alpharetta, Ga. The second barrier layer 150 and optoelectronic device 140, electrically conductive connectors 302 and 308, and contacts 118 and 120 are then aligned and layed up in preparation for lamination process at a temperature between 90° C. and 130° C., preferably at 120° C., and a pressure of 1 psi to 30 psi, and preferably 15 psi, for a time between 1 second and 10 minutes, and preferably 30 seconds. In the resulting package, the electrically conductive connectors 302 and 308 make electrical connections with contacts 118 and 120 through the blocks 306 and 312. The apertures 304 and 310, connectors 302 and 308 and blocks 306 and 312 can be, optionally, centered and aligned.
Various lamination means are possible, including pouch lamination, roll lamination and hot press lamination, and process parameters depend on the equipment utilized. It is apparent that release films, press pads, and tooling plates are necessary to perform these laminations. Moreover, steps to clean and remove moisture from all package materials may be performed during processing. For example, the second barrier layer 150 may be baked at 80° C. for 12 hours under vacuum to eliminate moisture; however, other conditions may be used, including shorter times at higher temperatures under an inert atmosphere. The conditions will depend on the prior environmental exposure of the materials.
The conductive bus lines 402 and 404 are made from conductive material like aluminum, steel, nickel, or brass. At least one of the thin electrically conductive connectors 302 and 308 is electrically coupled to one of the conductive bus line 402 and 404 by means of conductive adhesive material. The conductive bus lines 402 and 404 are extended out from the at least one of the apertures 304 and 310. According to certain embodiments, the conductive bus lines are disposed between the first barrier layer 130 and the optoelectronic device 140. According to other embodiments, the conductive bus lines are disposed between the optoelectronic device 140 and the second barrier layer 150. The connectors 302 and 308 are attached perpendicular to the bus lines. According to certain embodiments, the connectors 302 and 308 are attached parallel to the bus lines 402 and 404.
In the multi-pixel configuration of optoelectronic devices 140, where individual optoelectronic devices 140 are packaged separately and then integrated in a series configuration, the conductive bus lines 402 and 404 are extended out of one packaged optoelectronic device 200 from the apertures and extended to another packaged optoelectronic device 200 where they are electrically coupled to cathode and anode contacts of the other packaged optoelectronic device 200, respectively.
In the packaged optoelectronic device 200, according to one embodiment, all electrically conductive connectors 308 connected to the cathode contact 118 of the optoelectronic devices 140, 202, 204, and 206 are connected to the conductive bus lines 402. Further, all the electrically conductive connectors 302 connected to the anode contact 120 of the optoelectronic devices 140, 202, 204, and 206 are connected the conductive bus lines 404. Further, in certain embodiments, the conductive bus line 402 is electrically coupled with the cathode contacts 118 of the optoelectronic devices 140, 202, 204, and 206 through direct contact, i.e. not through electrically conductive connectors 308. In certain embodiments, the cathode contacts 118 are electrically coupled to the power source through the conductive bus line 402, whereas the anode contacts 120 are electrically coupled to the power source through the electrically conductive connectors 302. Contact between the conductive bus lines 402 is avoided by disposing the conductive bus lines 402 in parallel fashion along the width of the packaged optoelectronic device 200
According to certain embodiments, insulation layer 502 is deposited along a periphery of the apertures 304 and 310. The insulation layer 502 protects thin electrically conductive connectors 302 and 308, and/or the conductive bus lines 402 from coming in contact with other components of the packaged optoelectronic device 200 and cause electric shorting.
Various embodiments of the packaged optoelectronic device and method for manufacturing provide for flexible packaged optoelectronic devices with low cost of production. Further, the packaged optoelectronic device described in the application provides for a solution to the problem of moisture and oxygen ingression observed in optoelectronic packaging.
It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. While the dimensions and types of materials described herein are intended to define the parameters of the invention, they are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to those of ordinary skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended description, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” etc. if any, are used merely as labels, and are not intended to impose numerical or positional requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. §112, sixth paragraph, unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.
This written description uses examples to disclose several embodiments of the invention, including the best mode, and also to enable any person of ordinary skill in the art to practice the embodiments of invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural of said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising,” “including,” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property.
While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.
