David B Joyce

US Patent:

6368403, Apr 9, 2002

Filed:

Feb 25, 2000

Appl. No.:

09/512947

Inventors:

Frederick Schmid - Marblehead MA
Chandra P. Khattak - Danvers MA
David B. Joyce - Marblehead MA

Assignee:

Crystal Systems, Inc. - Salem MA

International Classification:

C30B 1318

US Classification:

117 79, 117204, 423328

Abstract:

An apparatus for purifying metallurgical grade silicon to produce solar grade silicon has a container for holding molten silicon and one or more torches for providing oxygen and hydrogen gas to heat the molten silicon so that the reaction time is prolonged, to create turbulence, and to introduce silica powder and water vapor for reactions with molten silicon. The molten silicon is then directionally solidified.

US Patent:

7344596, Mar 18, 2008

Filed:

Aug 25, 2005

Appl. No.:

11/212027

Inventors:

Frederick Schmid - Marblehead MA, US
Chandra P. Khattak - Danvers MA, US
David B. Joyce - Marblehead MA, US

Assignee:

Crystal Systems, Inc. - Salem MA

International Classification:

C30B 11/00
C30B 35/00

US Classification:

117206, 117201, 117202, 117204, 117207, 117223, 117900, 117932, 117936

Abstract:

To reduce the heat input to the bottom of the crucible and to control heat extraction independently of heat input, a shield can be raised between a heating element and a crucible at a controlled speed as the crystal grows. Other steps could include moving the crucible, but this process can avoid having to move the crucible. A temperature gradient is produced by shielding only a portion of the heating element; for example, the bottom portion of a cylindrical element can be shielded to cause heat transfer to be less in the bottom of the crucible than at the top, thereby causing a stabilizing temperature gradient in the crucible.

US Patent:

7918936, Apr 5, 2011

Filed:

Oct 19, 2007

Appl. No.:

11/875078

Inventors:

Frederick Schmid - Marblehead MA, US
Chandra P. Khattak - Danvers MA, US
David B. Joyce - Marblehead MA, US

Assignee:

GT Crystal Systems, LLC - Salem MA

International Classification:

C30B 29/04

US Classification:

117 81, 117 82, 117 83, 117 21, 117 25

Abstract:

To reduce the heat input to the bottom of the crucible and to control heat extraction independently of heat input, a shield can be raised between a heating element and a crucible at a controlled speed as the crystal grows. Other steps could include moving the crucible, but this process can avoid having to move the crucible. A temperature gradient is produced by shielding only a portion of the heating element; for example, the bottom portion of a cylindrical element can be shielded to cause heat transfer to be less in the bottom of the crucible than at the top, thereby causing a stabilizing temperature gradient in the crucible.

US Patent:

8177910, May 15, 2012

Filed:

Mar 1, 2011

Appl. No.:

13/037841

Inventors:

Frederick Schmid - Marblehead MA, US
Chandra P. Khattak - Danvers MA, US
David B. Joyce - Marblehead MA, US

Assignee:

GT Crystal Systems, LLC - Salem MA

International Classification:

C30B 15/14

US Classification:

117 20, 117 21, 117 25, 117218

Abstract:

To reduce the heat input to the bottom of the crucible and to control heat extraction independently of heat input, a shield can be raised between a heating element and a crucible at a controlled speed as the crystal grows. Other steps could include moving the crucible, but this process can avoid having to move the crucible. A temperature gradient is produced by shielding only a portion of the heating element; for example, the bottom portion of a cylindrical element can be shielded to cause heat transfer to be less in the bottom of the crucible than at the top, thereby causing a stabilizing temperature gradient in the crucible.

US Patent:

8329133, Dec 11, 2012

Filed:

Oct 28, 2009

Appl. No.:

12/607773

Inventors:

Frederick Schmid - Marblehead MA, US
David B Joyce - Marblehead MA, US

Assignee:

GT Crystal Systems, LLC - Salem MA

International Classification:

C01B 33/02

US Classification:

423348

Abstract:

A method and apparatus for refining metallurgical silicon to produce solar grade silicon for use in photovoltaic cells. A crucible in a vacuum furnace receives a mixture of metallurgical silicon and a reducing agent such as calcium disilicide. The mix is melted in non-oxidizing conditions within the furnace under an argon partial pressure. After melting, the argon partial pressure is decreased to produce boiling and the process ends with directional solidification. The process reduces impurities, such as phosphorus, to a level compatible with solar-grade silicon and reduces other impurities significantly.

US Patent:

20060227113, Oct 12, 2006

Filed:

Apr 6, 2005

Appl. No.:

10/907581

Inventors:

David Joyce - Belmont MA, US
Daniel Stearns - Canton MA, US

Assignee:

GENERAL ELECTRIC COMPANY - Schenectady NY

International Classification:

G09G 5/00

US Classification:

345173000

Abstract:

An actuator configured for use with an infrared (IR) touch screen device includes a flexible body having a cutout portion formed therein for viewing a display region of the touch screen device. One or more input buttons are formed in the flexible body, the one or more input buttons configured for alignment with corresponding keypad locations on the touch screen device. The one or more input buttons further include a reflective surface on a back side thereof for directly contacting the corresponding keypad areas on the touch screen device when the one or more buttons are fully depressed.

US Patent:

20110048316, Mar 3, 2011

Filed:

Sep 1, 2010

Appl. No.:

12/873388

Inventors:

Frederick Schmid - Marblehead MA, US
David B. Joyce - Marblehead MA, US
John Brouillette - Hudson NH, US
Daniel P. Betty - Andover MA, US
Ryan Philpott - Andover MA, US

Assignee:

GT CRYSTAL SYSTEMS, LLC - Salem MA

International Classification:

C30B 11/02

US Classification:

117 73, 117206, 117202

Abstract:

A method for minimizing unwanted ancillary reactions in a vacuum furnace used to process a material, such as growing a crystal. The process is conducted in a furnace chamber environment in which helium is admitted to the furnace chamber at a flow rate to flush out impurities and at a predetermined pressure to achieve thermal stability in a heat zone, to minimize heat flow variations and to minimize temperature gradients in the heat zone. During cooldown helium pressure is used to reduce thermal gradients in order to increase cooldown rates.

US Patent:

20110188962, Aug 4, 2011

Filed:

Feb 1, 2010

Appl. No.:

12/697656

Inventors:

David Alfred JOYCE - Billerica MA, US

International Classification:

F16B 21/18

US Classification:

411353

Abstract:

A captive fastener assembly that employs a concentric collar protrusion protruds from the bottom circular edge of the screw hole, surrounds the lower transitional shaft of the fastener to hold the fastener steadily aligned with the receiving hole when the to-be-fastened parts as being opened or closed.