News Column

Patent Application Titled "Method and Apparatus for Depositing Films" Published Online

July 3, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- According to news reporting originating from Washington, D.C., by VerticalNews journalists, a patent application by the inventors BULOVIC, Vladimir (Lexington, MA); CHEN, Jianglong (San Jose, CA); MADIGAN, Conor Francis (San Francisco, CA); SCHMIDT, Martin A. (Reading, MA), filed on July 5, 2013, was made available online on June 19, 2014.

No assignee for this patent application has been made.

Reporters obtained the following quote from the background information supplied by the inventors: "The disclosure relates to a method and apparatus for efficiently depositing patterns of films on a substrate. More specifically, the disclosure relates to a method and apparatus for depositing films on a substrate which may form part of an LED or other types of display.

"The manufacture of organic light emitting devices (OLEDs) requires depositing one or more organic films on a substrate and coupling the top and bottom of the film stack to electrodes. The film thickness is a prime consideration. The total layer stack thickness is about 100 nm and each layer is optimally deposited uniformly with an accuracy of better than +/-1 nm. Film purity is also important. Conventional apparatuses form the film stack using one of two methods: (1) thermal evaporation of organic material in a relative vacuum environment and subsequent condensation of the organic vapor on the substrate; or, (2) dissolution of organic material into a solvent, coating the substrate with the resulting solution, and subsequent removal of the solvent.

"Another consideration in depositing the organic thin films of an OLED is placing the films precisely at the desired location. There are two conventional technologies for performing this task, depending on the method of film deposition. For thermal evaporation, shadow masking is used to form OLED films of a desired configuration. Shadow masking techniques require placing a well-defined mask over a region of the substrate followed by depositing the film over the entire substrate area. Once deposition is complete, the shadow mask is removed. The regions exposed through the mask define the pattern of material deposited on the substrate. This process is inefficient, as the entire substrate must be coated, even though only the regions exposed through the shadow mask require a film. Furthermore, the shadow mask becomes increasingly coated with each use, and must eventually be discarded or cleaned. Finally, the use of shadow masks over large areas is made difficult by the need to use very thin masks (to achieve small feature sizes) that make said masks structurally unstable. However, the vapor deposition technique yields OLED films with high uniformity and purity and excellent thickness control.

"For solvent deposition, ink jet printing can be used to deposit patterns of OLED films. Ink jet printing requires dissolving organic material into a solvent that yields a printable ink. Furthermore, ink jet printing is conventionally limited to the use of single layer OLED film stacks, which typically have lower performance as compared to multilayer stacks. The single-layer limitation arises because printing typically causes destructive dissolution of any underlying organic layers. Finally, unless the substrate is first prepared to define the regions into which the ink is to be deposited, a step that increases the cost and complexity of the process, ink jet printing is limited to circular deposited areas with poor thickness uniformity as compared to vapor deposited films. The material quality is also typically lower, due to structural changes in the material that occur during the drying process and due to material impurities present in the ink. However, the ink jet printing technique is capable of providing patterns of OLED films over very large areas with good material efficiency.

"No conventional technique combines the large area patterning capabilities of ink jet printing with the high uniformity, purity, and thickness control achieved with vapor deposition for organic thin films. Because ink jet processed single layer OLED devices continue to have inadequate quality for widespread commercialization, and thermal evaporation remains impractical for scaling to large areas, it is a major technological challenge for the OLED industry to develop a technique that can offer both high film quality and cost-effective large area scalability.

"Finally, manufacturing OLED displays may also require the patterned deposition of thin films of metals, inorganic semiconductors, and/or inorganic insulators. Conventionally, vapor deposition and/or sputtering have been used to deposit these layers. Patterning is accomplished using prior substrate preparation (e.g., patterned coating with an insulator), shadow masking as described above, and when a fresh substrate or protective layers are employed, conventional photolithography. Each of these approaches is inefficient as compared to the direct deposition of the desired pattern, either because it wastes material or requires additional processing steps. Thus, there is a need for these materials as well for a method and apparatus for depositing high-quality, cost effective, large area scalable films."

In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventors' summary information for this patent application: "In one embodiment, the disclosure is directed to an apparatus for depositing ink on a substrate, the apparatus comprising: a chamber for receiving ink; a discharge nozzle having an inlet port and an outlet port, the discharge nozzle receiving a quantity of ink from the chamber at the inlet port and dispensing the quantity of ink from the outlet port; and a dispenser for metering the quantity of ink from the chamber to the inlet port of the discharge nozzle; wherein the chamber receives ink in liquid form having a plurality of suspended particles and the quantity of ink is pulsatingly metered from the chamber to the discharge nozzle; and the discharge nozzle evaporates the carrier liquid and deposits the substantially solid particles on the substrate.

"In another embodiment, the disclosure relates to a method for depositing ink on a substrate, the method comprising: using a pulsating energy having a first frequency to meter a quantity of ink to a discharge nozzle, the ink defined by a plurality of solid particles in a carrier liquid; receiving the metered quantity of ink at the discharge nozzle and evaporating the carrier liquid from the metered quantity of ink to provide a quantity of substantially solid ink particles; dispensing the substantially solid ink particles from the discharge nozzle and depositing the substantially solid ink particles on the substrate; and wherein at least a portion of the substantially solid ink particles are converted to a vapor phase during discharge from the discharge nozzle, directed to the substrate as a vapor, and condense on a surface of the substrate in substantially solid form.

"In still another embodiment, the disclosure relates to a method for depositing ink on a substrate, the method comprising: providing liquid ink to a chamber, the liquid ink defined by a plurality of suspended particles in a carrier liquid; pulsatingly energizing a dispenser to meter a quantity of liquid ink from the chamber to a discharge nozzle, the quantity of liquid ink metered as a function of a frequency of at least one of a pulse amplitude, a pulse duration or a pulse frequency; receiving the metered quantity of ink at a discharge nozzle, the discharge nozzle having a plurality of conduits for directing the metered quantity of ink; heating the metered quantity of ink at the plurality of conduits to evaporate the carrier liquid; and discharging the plurality of suspended particles from the discharge nozzle onto the substrate; wherein the plurality of suspended particles are deposited on the substrate in substantially solid form.

"In still another embodiment, the disclosure relates to a system for depositing ink on a substrate, the system comprising: a chamber having a quantity of ink, the ink defined by a plurality of suspended ink particles in a carrier liquid; a discharge nozzle proximal to the chamber for receiving a metered quantity of ink pulsatingly delivered from the chamber by a dispenser, the discharge nozzle evaporating the carrier liquid to form a substantially solid quantity of ink particles; and a controller in communication with the discharge nozzle, the controller energizing the discharge nozzle to communicate the substantially solid quantity of ink particles from the discharge nozzle onto the substrate.

"In still another embodiment, the disclosure relates to a system for depositing ink on a substrate, the system comprising: a chamber for receiving a quantity of ink, the ink having a plurality of suspended particles in a carrier liquid; an ink dispenser for pulsatingly metering a quantity of ink delivered from the chamber; a discharge nozzle for receiving a metered quantity of ink delivered from the chamber and evaporating the carrier liquid from the received quantity of ink to form a substantially solid quantity of particles; a first controller in communication with the ink dispenser, the first controller pulsatingly energizing the dispenser to meter a quantity of ink delivered from the chamber; and a second controller in communication with the discharge nozzle, the second controller energizing the discharge nozzle to communicate the metered quantity of particles from the discharge nozzle onto the substrate.

"In still another embodiment, the disclosure relates to a method for providing accurate deposition of ink on a substrate, the method comprising: providing a quantity of ink to a chamber, the ink having a plurality of suspended particles in a carrier liquid; metering at least a portion of the ink delivered from the chamber to an inlet of a discharge nozzle by activating a dispenser; receiving the metered ink at a discharge nozzle, the discharge nozzle having an inlet port and an outlet port; transporting the metered ink from the inlet port to the outlet port of the discharge nozzle forming substantially solid particles; and depositing the substantially solid particles from the outlet port of the discharge nozzle onto a substrate by energizing the discharge nozzle to pulsatingly eject at least a portion of the substantially solid particles onto the substrate.

"In yet another embodiment, the disclosure relates to a system for accurate deposition of ink on a substrate, the system comprising: a storage means for storing a composition of ink particles in a carrier liquid; a metering means in communication with the storage means to pulsatingly meter at least a portion of the composition; a transporting means for transporting the ink from the chamber to a discharge nozzle; an evaporating means for evaporating the carrier liquid to form a substantially solid quantity of ink particles at the discharge nozzle; and a discharging means for discharging the substantially solid ink particles from the discharge nozzle onto a substrate.

"In still another embodiment, the disclosure relates to an apparatus for depositing particles on a substrate, the apparatus comprising: a chamber for receiving ink, the chamber receiving ink in liquid form having a plurality of particles in a carrier liquid; a dispenser associated with the chamber, the dispenser metering a quantity of ink delivered from the chamber to a discharge nozzle, the discharge nozzle evaporating the carrier liquid to form a substantially solid quantity of ink particles; wherein the discharge nozzle rotates axially relative to the chamber to discharge the substantially solid quantity of ink particles; and wherein the discharge nozzles deposits the substantially solid particles onto a substrate.

"In still another embodiment, the disclosure relates to a system for controlling a printing device, the system comprising: a first controller having a first processor circuit in communication with a first memory circuit, the first memory circuit containing instructions for directing the first processor to: identify a plurality of chambers, each chamber receiving liquid ink having a plurality of dissolved or suspended particles in a carrier liquid, engage each of the plurality of chambers to meter a quantity of liquid ink for dispensing; a second controller having a second processor circuit in communication with a second memory circuit, the second memory circuit containing instructions for directing the second processor to: identify a plurality of discharge nozzles, each of the plurality of discharge nozzles receiving the quantity of liquid from a corresponding one of the plurality of chambers, activate each of the plurality of the discharge nozzles to evaporate at least a part of the carrier liquid, direct each of the plurality of discharge nozzles to deposit substantially solid ink particles onto a substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

"These and other embodiments of the disclosure will be discussed with reference to the following non-limiting and exemplary illustrations, in which like elements are numbered similarly, and where:

"FIG. 1A is a schematic representation of an exemplary print-head having a thermal ink dispensing mechanism according to one embodiment of the disclosure;

"FIG. 1B is a schematic representation of an exemplary print-head having a piezoelectric ink dispensing mechanism according to one embodiment of the disclosure;

"FIG. 1C is a schematic representation of an exemplary print-head having physically separated chamber housing and discharge nozzle housing portions according to one embodiment of the disclosure;

"FIG. 1D is a schematic representation of an exemplary print-head having physically separated chamber housing and discharge nozzle housing portions, and isolation space between the discharge nozzle and the associated housing, according to one embodiment of the disclosure;

"FIG. 1E shows a top view of an exemplary implementation of the discharge nozzle;

"FIGS. 2A-2D schematically illustrate the process of depositing a solvent-free material using a print-head apparatus according to an embodiment of the disclosure;

"FIG. 3A schematically illustrates a print-head apparatus having multiple discharge nozzles and using thermal ink dispensing elements;

"FIG. 3B schematically illustrates a print-head apparatus having multiple discharge nozzles and using piezoelectric ink dispensing elements;

"FIG. 4 is a schematic representation of a print-head apparatus with multiple reservoirs;

"FIG. 5 schematically illustrates an apparatus for depositing thin films of material using one or more print-heads, at least one of which having one or more discharge nozzles, and a positioning system;

"FIG. 6 schematically illustrates a micro-porous discharge nozzle having micro-pores with tapered sidewalls;

"FIG. 7 shows exemplary micro-pore patterns for use in a micro-porous discharge nozzle;

"FIGS. 8A and 8B (collectively, FIG. 8) schematically illustrate a dye sublimation printer in accordance with one embodiment of the disclosure;

"FIGS. 9A and 9B illustrate the use of the discharge apparatus for spatially localized chemical synthesis;

"FIGS. 9C and 9D depict the use of a discharge apparatus as a micro reactor;

"FIG. 10A is a schematic representation of an exemplary print-head in accordance with an embodiment of the disclosure;

"FIGS. 10B-10E illustrate a method for depositing a film using the print-head shown in FIG. 10A;

"FIG. 11A schematically illustrates a thermally activated print-head according to one embodiment of the disclosure;

"FIGS. 11B-11E illustrate a method for depositing a film using the print-head apparatus shown in FIG. 11A;

"FIG. 12 illustrates a method for depositing particles on a substrate according to one embodiment of the disclosure; and

"FIG. 13 is a schematic representation of a control system for controlling a print-head having a discharge nozzle, according to one embodiment of the disclosure."

For more information, see this patent application: BULOVIC, Vladimir; CHEN, Jianglong; MADIGAN, Conor Francis; SCHMIDT, Martin A. Method and Apparatus for Depositing Films. Filed July 5, 2013 and posted June 19, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=5058&p=102&f=G&l=50&d=PG01&S1=20140612.PD.&OS=PD/20140612&RS=PD/20140612

Keywords for this news article include: Patents.

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Source: Politics & Government Week


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