Chin Y ChangFlushing, NY

6376999, Apr 23, 2002

Sep 15, 2000

09/663807

Yushan Li - Ossining NY
Chin Chang - Yorktown Heights NY

Philips Electronics North America Corporation - New York NY

H05B 3702

315307, 315224, 315324, 315DIG 5

An LCD backlight inverter that comprises a power stage that includes a first power switch and a second power switch that powers one or more cold cathode fluorescent lamps. A controller generates control signals, receives an IC supply input signal having a voltage level equaling or exceeding a prescribed threshold level, and provides a steady-state internal oscillation that drives said first and second power switches. A transient prevention circuit maintains said second power switch in a nonconducting state until at least a time at which said IC supply input signal reaches said prescribed voltage threshold. Alternatively, a transient prevention circuit maintains said second power switch in a nonconducting state until at least a time at which said IC supply input signal reaches said prescribed voltage threshold, and additionally prevents the controller oscillator from generating said internally generated oscillation until at least a time at which a supply voltage to the IC reaches a threshold value.

6441558, Aug 27, 2002

Dec 7, 2000

09/732197

Subramanian Muthu - Tarrytown NY
Chin Chang - Yorktown Heights NY
Gert Bruning - Sleepy Hollow NY

Koninklijke Philips Electronics N.V. - Eindhoven

H05B 3702

315149, 315291, 315118

An LED luminary system for providing power to LED light sources to generate a desired light color comprises a power supply stage configured to provide a DC current signal. A light mixing circuit is coupled to said power supply stage and includes a plurality of LED light sources with red, green and blue colors to produce various desired lights with desired color temperatures. A controller system is coupled to the power supply stage and is configured to provide control signals to the power supply stage so as to maintain the DC current signal at a desired level for maintaining the desired light output. The controller system is further configured to estimate lumen output fractions associated with the LED light sources based on junction temperature of the LED light sources and chromaticity coordinates of the desired light to be generated at the light mixing circuit. The light mixing circuit further comprises a temperature sensor for measuring the temperature associated with the LED light sources and a light detector for measuring lumen output level of light generated by the LED light sources. Based on the temperatures measured, the controller system determines the amount of output lumen that each of the LED light sources need to generate in order to achieve the desired mixed light output, and the light detector in conjunction with a feedback loop maintains the required lumen output for each of the LED light sources.

6495964, Dec 17, 2002

Dec 27, 2000

09/749154

Subramanian Muthu - Ossining NY
Chin Chang - Yorktown Heights NY

Koninklijke Philips Electronics N.V. - Eindhoven

H05B 3702

315149, 315312, 315307, 315360, 250214 AL, 250214 C, 250553

The combined light output (chromaticity) of a white light emitting LED luminaire is electronically controlled based on measurements by a single photodiode arranged to measure the light outputs of at least a plurality of the LEDs in the array. This is accomplished by measuring the light output of the LEDs in each color separately in a sequence of time pulses. For an array of red, green, and blue LEDs there are three time pulses in a measuring sequence. During each time pulse, the current for the color being measured is turned off. The response time of a typical photodiode is extremely short, so the measuring sequence can be performed in a sufficiently short time that an-observer will not detect it (e. g. 10 ms). Measured light outputs for the colors are compared to desired outputs, which may be set by user controls, and changes to the power supply for the color blocks are made as necessary. Chromaticity is thus automatically controlled without regard to the factors which may cause it to change.

6509696, Jan 21, 2003

Mar 22, 2001

09/815089

Gert Bruning - Sleepy Hollow NY
Chin Chang - Yorktown Heights NY

Koninklijke Philips Electronics N.V. - Eindhoven

H05B 4116

315246, 315DIG 5, 315209 R

A capacitively coupled fluorescent lamp package having a capacitively coupled fluorescent lamp; an inverter circuit for driving the lamp; and supply nodes for receiving a supply voltage is disclosed. The capacitively coupled fluorescent lamp package includes a resonant circuit lamp driving scheme for driving the capacitively coupled fluorescent lamp. The driving scheme reduces parasitic capacitance leakage current; compensates the reactive power using the secondary side leakage inductance in order to have the resonant frequency approximately equal the inverter circuit operating frequency for current source-type driven circuits; and forms a series resonant sub-circuit with the embedded ballasting capacitor and the secondary side leakage inductance for voltage source-type driven circuits, such that the resonant frequency is substantially less than the inverter circuit operating frequency and that the lamp current is properly shaped along with current ballasting.

6510995, Jan 28, 2003

Mar 16, 2001

09/810142

Subramanian Muthu - Ossining NY
Chin Chang - Yorktown NY

Koninklijke Philips Electronics N.V. - Eindhoven

G06K 714

235454, 23546225

A device for controlling and adjusting a display light for a retail display system comprising a computer associated with plural light sources for adjusting the light sources to optimally display particular products. The light sources are adjusted based upon a prestored table specifying optimal lighting conditions for each of plural products, and a feedback loop that feeds back actual lighting conditions.

6597842, Jul 22, 2003

May 21, 2001

09/862146

Jyl Ren Dent - Rolling Heights CA
Amado Cordova - Venice CA
Ronald J. Michal - Wrightwood CA
Chin L. Chang - Walnut CA
Trong-Huang Lee - Walnut CA

Copley Networks, Inc. - City of Industry CA

G02B 642

385 39, 385 24, 385 33, 385 42, 359124, 359127, 359131

An optical interleaver. The interleaver is based upon the Mach Zender interferometer. At least one of the optical paths joining opposed couplers of the arrangement includes an optical image transfer element intermediate the ends of fibers associated with the couplers. In one embodiment, the optical image transfer element is a single imaging lens whereas, in another embodiment, the element consists of an aligned pair of collimating lenses. During fabrication, optical positioning stages support the optical image transfer element and fiber ends to permit ready adjustment of , the optical path length difference between the arms of the interleaver, to assure predetermined optical channel spacing of an input DWDM signal.

6753661, Jun 22, 2004

Jun 17, 2002

10/173346

Subramanian Muthu - Ossining NY
Frank J. Schuurmans - Valkenswaard, NL
Chin Chang - Yorktown Heights NY
James Gaines - Mohegan Lake NY

Koninklijke Philips Electronics N.V. - Eindhoven

G05F 100

315307, 315149, 315224, 315291, 315312, 362234, 362253

Apparatus and method for backlighting an electronic display with LEDs to control luminosity, radiometric power, and color levels by means of feedback control through a microprocessor, thereby maintaining white backlight at substantially constant levels, which can be chosen by an operator.

6888529, May 3, 2005

Dec 12, 2000

09/735151

Gert Bruning - Sleepy Hollow NY, US
Chin Chang - Yorktown Heights NY, US

Koninklijke Philips Electronics N.V. - Eindhoven

G09G003/36

345102, 345 82, 345 46, 345 88, 349 61

A backlight for an LCD display comprised of an array of LEDs. The backlight may be driven and controlled by a fast pulse power converter, thus providing a response time for the backlight on the order of microseconds. The backlight may thus be used for image display, for example, in the depiction of images in a video input to the LCD and removal of image artifacts.