Patents by Inventor David S. Y. Hsu
David S. Y. Hsu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6402985Abstract: Doped phosphors (e.g., metal orthosilicates) are made by adding solid particulate precursor to a solution of an alkoxide precursor and a dopant precursor before hydrolysis is allowed to occur. The mixture is then allowed to hydrolyze, resulting in a sol-gel condensation reaction. The solid particulate precursor can be fumed silica, and acts as a nucleation site for the sol-gel reaction product. After the sol-gel reaction, the mixture is dried and fired to form phosphors. The phosphors are especially suitable for applications in which there is low voltage operation.Type: GrantFiled: March 17, 2000Date of Patent: June 11, 2002Assignee: The United States of America as represented by the Secretary of the NavyInventors: David S. Y. Hsu, Yongchi Tian
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Publication number: 20020055319Abstract: A field emitter cell includes a thin-film-edge emitter normal to the gate layer. The field emitter cell may include a conductive substrate layer, an insulator layer having a perforation, a gate layer having a perforation, an emitter layer, and other optional layers. The perforation in the gate layer is larger and concentrically offset with respect to the perforation in the insulating layer and may be of a tapered construction. Alternatively, the perforation in the gate layer may be coincident with, or larger or smaller than, the perforation in the insulating layer, provided that the gate layer is shielded from the emitter from a direct line-of-sight by a nonconducting standoff layer. Optionally, the thin-film-edge emitter may include incorporated nanofilaments. The field emitter cell has low gate current, making it useful for various applications such as field emitter displays, high voltage power switching, microwave, RF amplification and other applications that require high emission currents.Type: ApplicationFiled: December 12, 2001Publication date: May 9, 2002Inventor: David S.Y. Hsu
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Patent number: 6379583Abstract: Nanocrystalline phosphors are formed within a bicontinuous cubic phase.Type: GrantFiled: December 21, 1999Date of Patent: April 30, 2002Assignee: The United States of America as represented by the Secretary of the NavyInventors: Henry F. Gray, Jianping Yang, David S. Y. Hsu, Banhalli R. Ratna, Syed B. Qadri
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Publication number: 20020042241Abstract: A field emitter cell includes a thin-film-edge emitter normal to the gate layer. The field emitter cell may include a conductive substrate layer, an insulator layer having a perforation, a gate layer having a perforation, an emitter layer, and other optional layers. The perforation in the gate layer is larger and concentrically offset with respect to the perforation in the insulating layer and may be of a tapered construction. Alternatively, the perforation in the gate layer may be coincident with, or larger or smaller than, the perforation in the insulating layer, provided that the gate layer is shielded from the emitter from a direct line-of-sight by a nonconducting standoff layer. Optionally, the thin-film-edge emitter may include incorporated nanofilaments. The field emitter cell has low gate current, making it useful for various applications such as field emitter displays, high voltage power switching, microwave, RF amplification and other applications that require high emission currents.Type: ApplicationFiled: December 12, 2001Publication date: April 11, 2002Inventor: David S. Y. Hsu
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Patent number: 6333598Abstract: A field emitter cell includes a thin-film-edge emitter normal to the gate layer. The field emitter cell may include a conductive substrate layer, an insulator layer having a perforation, a gate layer having a perforation, an emitter layer, and other optional layers. The perforation in the gate layer is larger and concentrically offset with respect to the perforation in the insulating layer and may be of a tapered construction. Alternatively, the perforation in the gate layer may be coincident with, or larger or smaller than, the perforation in the insulating layer, provided that the gate layer is shielded from the emitter from a direct line-of-sight by a nonconducting standoff layer. Optionally, the thin-film-edge emitter may include incorporated nanofilaments. The field emitter cell has low gate current, making it useful for various applications such as field emitter displays, high voltage power switching, microwave, RF amplification and other applications that require high emission currents.Type: GrantFiled: January 7, 2000Date of Patent: December 25, 2001Assignee: The United States of America as represented by the Secretary of the NavyInventors: David S. Y. Hsu, Henry F. Gray
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Patent number: 6168491Abstract: A field emitter cell includes a thin film edge emitter normal to a gate layer. The field emitter is a multilayer structure including a low work function material sandwiched between two protective layers. The field emitter may be fabricated from a composite starting structure including a conductive substrate layer, an insulation layer, a standoff layer and a gate layer, with a perforation extending from the gate layer into the substrate layer. The emitter material is conformally deposited by chemical beam deposition along the sidewalls of the perforation. Alternatively, the starting material may be a conductive substrate having a protrusion thereon. The emitter layer, standoff layer, insulation layer, and gate layer are sequentially deposited, and the unwanted portions of each are preferentially removed to provide the desired structure.Type: GrantFiled: November 29, 1999Date of Patent: January 2, 2001Assignee: The United States of America as represented by the Secretary of the NavyInventors: David S. Y. Hsu, Henry F. Gray
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Patent number: 6090200Abstract: Nanocrystalline phosphors are formed within a bicontinuous cubic phase. The phosphors are doped with an optimum concentration, of manganese, for example, corresponding to about one or less dopant ions per phosphor particle.Type: GrantFiled: November 18, 1997Date of Patent: July 18, 2000Inventors: Henry F. Gray, Jianping Yang, David S. Y. Hsu, Banhalli R. Ratna, Syed B. Qadri
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Patent number: 6084245Abstract: A field emitter cell includes a thin film edge emitter normal to a gate layer. The field emitter is a multilayer structure including a low work function material sandwiched between two protective layers. The field emitter may be fabricated from a composite starting structure including a conductive substrate layer, an insulation layer, a standoff layer and a gate layer, with a perforation extending from the gate layer into the substrate layer. The emitter material is conformally deposited by chemical beam deposition along the sidewalls of the perforation. Alternatively, the starting material may be a conductive substrate having a protrusion thereon. The emitter layer, standoff layer, insulation layer, and gate layer are sequentially deposited, and the unwanted portions of each are preferentially removed to provide the desired structure.Type: GrantFiled: March 23, 1998Date of Patent: July 4, 2000Assignee: The United States of America as represented by the Secretary of the NavyInventors: David S. Y. Hsu, Henry F. Gray
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Patent number: 5985173Abstract: Phosphors having a doped core are surrounded by a shell material. Additionally, these nanocrystalline phosphors, or larger phosphors formed by conventional or other processes may be surrounded by a shell that prevents or significantly reduces non-radiative recombination at the surface of the original phosphor.Type: GrantFiled: November 18, 1997Date of Patent: November 16, 1999Inventors: Henry F. Gray, Jianping Yang, David S. Y. Hsu, Banhalli R. Ratna
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Patent number: 5742121Abstract: A thin-film edge field emitter device includes a substrate having a first rtion and having a protuberance extending from the first portion, the protuberance defining at least one side-wall, the side-wall constituting a second portion. An emitter layer is disposed on the substrate including the second portion, the emitter layer being selected from the group consisting of semiconductors and conductors and is a thin-film including a portion extending beyond the second portion and defining an exposed emitter edge. A pair of supportive layers is disposed on opposite sides of the emitter layer, the pair of supportive layers each being selected from the group consisting of semiconductors and conductors and each having a higher work function than the emitter layer.Type: GrantFiled: June 5, 1996Date of Patent: April 21, 1998Assignee: The United States of America as represented by the Secretary of the NavyInventors: David S. Y. Hsu, Henry F. Gray
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Patent number: 5584740Abstract: A thin-film edge field emitter device includes a substrate having a first portion and having a protuberance extending from the first portion, the protuberance defining at least one side-wall, the side-wall constituting a second portion. An emitter layer is disposed on the substrate including the second portion, the emitter layer being selected from the group consisting of semiconductors and conductors and is a thin-film including a portion extending beyond the second portion and defining an exposed emitter edge. A pair of supportive layers is disposed on opposite sides of the emitter layer, the pair of supportive layers each being selected from the group consisting of semiconductors and conductors and each having a higher work function than the emitter layer.Type: GrantFiled: October 11, 1994Date of Patent: December 17, 1996Assignee: The United States of America as represented by the Secretary of the NavyInventors: David S. Y. Hsu, Henry F. Gray
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Patent number: 5459099Abstract: A non-optical method for the formation of sub-half micron holes, vias, or trenches within a substrate. For example, a substrate having at least two buttresses or a trench having a interbuttress distance or a width of 1.0 to 0.5 microns, respectively, is conformally or non-conformally lined with a layer material. Thereafter, the layer material from horizontal surfaces is removed to expose the substrate underneath while leaving the layer material attached to the essentially vertical walls of the buttresses or the trenches essentially intact, thereby, narrowing the interbuttress distance or the trench width, respectively, to sub-half micron dimensions. The exposed substrate surface is then subjected to anisotropic etching to form sub-half micron trenches, holes or vias in the substrate. Finally, the buttresses and layer material are removed from the substrate.Type: GrantFiled: November 17, 1994Date of Patent: October 17, 1995Assignee: The United States of America as represented by the Secretary of the NavyInventor: David S. Y. Hsu
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Patent number: 5420067Abstract: A non-optical method for the formation of sub-half micron holes, vias, or trenches within a substrate. For example, a substrate having at least two buttresses or a trench having a interbuttress distance or a width of 1.0 to 0.5 microns, respectively, is conformally or non-conformally lined with a layer material. Thereafter, the layer material from horizontal surfaces is removed to expose the substrate underneath while leaving the layer material attached to the essentially vertical walls of the buttresses or the trenches essentially intact, thereby, narrowing the interbuttress distance or the trench width, respectively, to sub-half micron dimensions. The exposed substrate surface is then subjected to anisotropic etching to form sub-half micron trenches, holes or vias in the substrate. Finally, the buttresses and layer material are removed from the substrate.Type: GrantFiled: September 20, 1993Date of Patent: May 30, 1995Assignee: The United States of America as represented by the Secretary of the NavyInventor: David S. Y. Hsu
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Patent number: 5382185Abstract: Thin-film edge field emitter devices are provided which are capable of low voltage operation. The method of manufacture of the devices takes advantage of chemical beam deposition and other thin-film fabrication techniques. Both gated and ungated devices are provided and all of the devices include a plurality of thin-films deposited on the side-wall of a non-flat substrate. The gated emitter devices include alternating conductive and electrically insulating layers, and upper parts of the latter are removed to expose the upper edges of the conductive layers, with a central one of these conductive layers comprising an emitter for emitting electrons. The emitter devices can be inexpensively produced with a high degree of precision and reproducibility without the need for expensive lithographic machines. The devices can be used in field emitter arrays employed as vacuum transistors, vacuum microelectronic analog and digital devices, and modulated or cold electron sources.Type: GrantFiled: March 31, 1993Date of Patent: January 17, 1995Assignee: The United States of America as represented by the Secretary of the NavyInventors: Henry F. Gray, David S. Y. Hsu
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Patent number: 5320978Abstract: A process for selectively depositing platinum on a conductive or semiconductive substrate has the steps of: patterning a polyimide layer on the substrate to have exposed areas and unexposed areas; and, at an operating temperature and an operating pressure, flowing a platinum precursor gas over the substrate.Type: GrantFiled: July 30, 1993Date of Patent: June 14, 1994Assignee: The United States of America as represented by the Secretary of the NavyInventor: David S. Y. Hsu
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Patent number: 5246879Abstract: Nanometer thick metallic layers are fabricated on trenches or holes (espelly vias) within a substrate by depositing, by thermal decomposition of a volatile metal-containing precursor gas in the presence of a carrier gas at low pressure, a metallic layer on a substrate surface on which one or more trenches or holes are formed. The metallic layer thus formed has an extremely small grain size, which permits the attainment of very high spatial resolution and thus permits the formation of extremely small trenches and holes, increasing the attainable memory/circuit density. This invention is useful in the fabrication of ultra-high density trench capacitors and ULSI microelectronic circuits.Type: GrantFiled: October 24, 1991Date of Patent: September 21, 1993Assignee: The United States of America as represented by the Secretary of the NavyInventors: David S. Y. Hsu, Henry F. Gray
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Patent number: 5110760Abstract: Nanometer thick vertical metallic structures are fabricated on a substrate by depositing a metallic layer on a substrate surface on which one or more buttresses are formed, etching the metallic layer to expose the horizontal surfaces of the substrate and the buttresses, and etching the substrate to remove the buttresses, thereby producing vertical structures on the substrate. The metallic layer is formed by thermal decomposition of a volatile metal-containing precursor gas in the presence of a carrier gas at low pressure, unlike that in conventional CVD reactors. The metallic layer thus formed has a grain size which is fraction of the thickness of the vertical structure.Type: GrantFiled: September 28, 1990Date of Patent: May 5, 1992Assignee: The United States of America as represented by the Secretary of the NavyInventor: David S. Y. Hsu
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Patent number: 4406763Abstract: Isotopes of carbon are separated by irradiating an isotopic mixture of methyl fluoride with a laser tuned to an absorption and of one of the isotopes, reacting the isotopic mixture with atomic bromine, whereby the excited isotopic form of methyl fluoride reacts at a faster rate than the other form, and separating the products.Type: GrantFiled: April 3, 1981Date of Patent: September 27, 1983Assignee: The United States of America as represented by the Secretary of the NavyInventors: David S. Y. Hsu, Thomas J. Manuccia, Jr.
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Patent number: 4399011Abstract: Isotopes of hydrogen are separated by reacting a normal alkane, its deuterated form, atomic bromine, a deactivating gas, and a isotopically selective vibrational sensitizer gas selected from the class consisting of carbon dioxide, carbon monoxide, nitrogen, and mixtures thereof and separating the products which are enriched in deuterium.Type: GrantFiled: January 3, 1981Date of Patent: August 16, 1983Assignee: The United States of America as represented by the Secretary of the NavyInventors: David S. Y. Hsu, Thomas J. Manuccia, Jr.