Christopher D Summers

US Patent:

6669867, Dec 30, 2003

Filed:

Nov 15, 2001

Appl. No.:

09/987697

Inventors:

Christopher J. Summers - Dunwoody GA
Young-rag Do - Seoul, KR
Do-hyung Park - Suwon, KR
Hong-geun Yang - Kyungki-do, KR

Assignee:

Georgia Tech Research Corporation - Atlanta GA
Samsung SDI Co., Ltd. - Suwon

International Classification:

C09K 1164

US Classification:

2523014R

Abstract:

A method of producing two visible light photons from an oxide-based phosphor doped with praseodymium (Pr) and including atoms of at least one activator in response to excitation with a single ultraviolet light photon. The method includes exciting the Pr of the oxide-based phosphor with a photon of ultraviolet light to excite an electron to an excited state, the excited electron falling to a lower energy state in a non-radiative transition and transferring energy to excite a first activator atom in the oxide-based phosphor, the first activator atom emitting a first photon of visible light, and the excited electron falling further to a lower energy state in a non-radiative transition, transferring energy to excite a second activator atom in the oxide-based phosphor, the second activator atom emitting a second photon of visible light. An oxide-based phosphor doped with praseodymium includes atoms of at least one activator and emitting two visible light photons in response to excitation by a single ultraviolet light photon.

US Patent:

6699523, Mar 2, 2004

Filed:

Jun 11, 2003

Appl. No.:

10/458624

Inventors:

Wounjhang Park - Dunwoody GA
Kazuhito Yasuda - Kani-Gifu, JP
Brent K. Wagner - Marietta GA
Christopher J. Summers - Dunwoody GA
Youngrag Do - Seoul, KR
Hong Guen Yang - Suwon, KR

Assignee:

Georgia Tech Research Corp. - Atlanta GA
Samsung Display Devices Co., Ltd. - Suwon

International Classification:

B05D 302

US Classification:

427215, 4273722, 428403

Abstract:

The present invention provides surface coated phosphors useful in field emission displays and vacuum fluorescent displays. The surface coated phosphor comprises a thin coating of rare earth oxide, e. g. , yttrium oxide, disposed on an uncoated phosphor such as a sulfide phosphor. The present invention further provides a process for preparing a surface coated phosphor comprising contacting the uncoated phosphor with a rare earth hydroxide gel solution to obtain a rare earth hydroxide gel coated phosphor, drying the gel coated phosphor to remove solvent residues, and heat treating the dried rare earth hydroxide gel coated phosphor. The surface coated phosphors of the present invention have improved cathodoluminescence efficiency, coulombic aging resistance, chemical, and/or oxidative stability.

US Patent:

6864110, Mar 8, 2005

Filed:

Oct 22, 2002

Appl. No.:

10/277285

Inventors:

Christopher J. Summers - Dunwoody GA, US
Hisham Menkara - Mableton GA, US
Bee Yin Janet Chua - Penang, MY

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

H01L021/00

US Classification:

438 22, 438466, 438678

Abstract:

The present invention provides a process and apparatus for selectively depositing materials on a semiconductor device, such as depositing phosphors or other optical materials on a light emitting diode (LED), using an electrophoretic deposition process. The semiconductor device comprises a p-side and an n-side. A first biasing voltage is applied between an anode and the p-side of the semiconductor device. A second biasing voltage is applied between the p-side and the n-side of the semiconductor device. The relative biasing of the p-side and the n-side determines where coating is deposited on the semiconductor device. An optional pre-coating process is used to deposit a high resistivity dielectric material, such as silica, on the semiconductor device. The pre-coating can even the electric field on the surface of the semiconductor device, where local features such as metal connections or passivation layers disturb the electric field during phosphor deposition without pre-coating.

US Patent:

6924233, Aug 2, 2005

Filed:

Mar 19, 2004

Appl. No.:

10/804759

Inventors:

Janet Bee Yin Chua - Penang, MY
Azlida Ahmad - Penang, MY
Christopher J. Summers - Dunwoody GA, US
Hisham Menkara - Mableton GA, US

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

H01L021/44

US Classification:

438678, 438 30, 438144, 438 28

Abstract:

Methods of coating a semiconductor device with phosphor particles are disclosed. In the methods, a bath is provided which contains suspended particles of a first phosphor material and suspended particles of a second phosphor material. The particles of the first phosphor material have a mean particle size in the range from about 1 micron to about 6 microns, and the particles of the second phosphor material have a mean particle size in the range from about 12 microns to about 25 microns, wherein the particle size distribution of the phosphor material in the bath is bimodal. The semiconductor device is disposed in the bath containing the suspended particles, and a first biasing voltage is applied between an anode in electrical contact with the bath and the p side to hold the anode at a positive voltage with respect to the p side. A second biasing voltage is applied between the p side and the n side. In particular embodiments, the method results in a substantially conformal coating of the phosphor particles being deposited on at least one surface of the semiconductor structure.

US Patent:

6982045, Jan 3, 2006

Filed:

Jul 28, 2003

Appl. No.:

10/628115

Inventors:

Hisham Menkara - Mableton GA, US
Christopher Summers - Atlanta GA, US

Assignee:

Phosphortech Corporation - Lirhia Springs GA

International Classification:

C09K 11/59

US Classification:

2523014F, 313486, 313503, 257 98, 257E33061

Abstract:

Provided herein are novel phosphors useful in the manufacture of white light emitting diodes. The phosphors provided by the invention are described by the formula:SrBaCaSiO:Euin which x, y, and z are each independently variable to be any value between about 0 and about 2, including without limitation 0. 001 and 2, and every thousandth therebetween, subject to the proviso that the sum of x, y, or z is equal to at least 1, and in which Eu is present in any amount between about 0. 0001% and about 5% by weight based upon the phosphor's total weight, wherein substantially all of the europium present is present in the divalent state. A phosphor according to the invention may optionally further comprise an element selected from the group consisting of: Ce, Mn, Ti, Pb, and Sn and is present in any amount between about 0. 0001% and about 5% by weight based on the phosphor's total weight. The silicate phosphor materials provided by the present invention do not require the addition of dissimilar blue and red phosphor compounds, and do not contain zinc and/or magnesium.

US Patent:

6987353, Jan 17, 2006

Filed:

Sep 15, 2003

Appl. No.:

10/661931

Inventors:

Hisham Menkara - Mableton GA, US
Christopher Summers - Atlanta GA, US

Assignee:

Phosphortech Corporation - Alpharetta GA

International Classification:

H01B 33/20

US Classification:

313503, 313502, 2523016 S

Abstract:

Provided herein are novel phosphors useful in the manufacture of white light emitting diodes. The phosphors provided by the invention are described by the formula: described by the formula:ZnSSe:Cu,Ain which x and y are each independently any value between 0 and about 1, subject to the proviso that the sum of x and y is equal to any number in the range of between about 0. 75 and about 1. 25; wherein A is optional and comprises at least one additional element selected from the group consisting of: Ag, Al, Ce, Tb, Cl, I, Mg, and Mn, including mixtures thereof, and wherein Cu is present in any amount between about 0. 0001% and about 5% in mole percent based on the total molar weight of said composition. Standard techniques used in phosphor deposition for the manufacture of light emitting diodes which comprise phosphors may be employed to produce LED's having a white light output when the phosphors of the invention are utilized.

US Patent:

6999669, Feb 14, 2006

Filed:

Aug 19, 2003

Appl. No.:

10/643746

Inventors:

Christopher J. Summers - Dunwoody GA, US
Wounjhang Park - Superior CO, US

Assignee:

Georgia Tech Research Corporation - Atlanta GA

International Classification:

G02B 6/00
G02B 5/06

US Classification:

385131, 65385, 385 14, 4271632

Abstract:

A photonic crystal includes a phosphor matrix and a plurality of defect regions. The phosphor matrix defines a plurality of substantially spherical voids arranged in a triangular lattice arrangement. The phosphor matrix has a first index of refraction. The plurality of defect regions is distributed in a subset of the spherical voids. Each defect region has a second index of refraction that is different from the first index of refraction.

US Patent:

7109648, Sep 19, 2006

Filed:

Mar 15, 2004

Appl. No.:

10/801082

Inventors:

Hisham Menkara - Mableton GA, US
Christopher Summers - Atlanta GA, US
Brent K. Wagner - Marietta GA, US

Assignee:

Phosphortech Inc. - Lithia Springs GA

International Classification:

H05B 33/14
C09K 11/56

US Classification:

313503, 2523016 S

Abstract:

Provided herein are novel phosphors useful in the manufacture of white light emitting diodes. The phosphors provided by the invention are described by the formulae:MA(SSe):Band/orMA(SSe):Bin which x, and y are each independently any value between 0 and 1, including 0 and 1 subject to the proviso that the sum of x and y is equal to any number in the range of between about 0. 75 and about 1. 25; M is at least one of Be, Mg, Ca, Sr, Ba, Zn; A is at least one of Al, Ga, In, Y, La, and Gd; and wherein the activator(s), B, comprises one or more element selected from the group consisting of: Eu, Ce, Cu, Ag, Al, Tb, Cl, Br, F, I, Mg, Pr, K, Na, and Mn, including mixtures comprising any two, any three, any four, any five, any six, any seven, or more of these elements in any proportion, and wherein the elements in these mixtures may each independently be present in any amount between 0. 0001% and about 10% in mole percent based on the total molar weight of said composition. Standard techniques used in phosphor deposition for the manufacture of light emitting diodes which comprise phosphors may be employed to produce LED's having a white light output when the phosphors of the invention are utilized.