William L Yu

US Patent:

6343871, Feb 5, 2002

Filed:

Mar 22, 2000

Appl. No.:

09/532305

Inventors:

William Yu - Silver Spring MD 20904

International Classification:

F21V 2100

US Classification:

362250, 362800, 362812, 362252

Abstract:

A body height adjustable electric bulb for illuminated sign wherein the bulb comprises a height adjusting unit inserted into an open end of a bulb body against friction between them such that the height of the bulb body can be adjusted by a force against such friction. A connector is fixed on a bulb head and connects to a joint end of the height adjusting unit such that the bulb body can be rotated by a proper torque.

US Patent:

6407511, Jun 18, 2002

Filed:

Jun 14, 2000

Appl. No.:

09/594125

Inventors:

Changgen Yang - Shanghai, P.R., CN
William Yu - Silver Spring MD 20904

International Classification:

H05B 3702

US Classification:

315224, 315247, 315DIG 5

Abstract:

An electronic ballast suitable for lighting control for a fluorescent lamp which includes a bridge rectifier for rectifying input commercial power supply voltage and a high frequency oscillator for feeding the fluorescent lamp a high frequency supply voltage, wherein the electronic ballast further comprises a linear active switching mode filter circuit for filtering the output of bridge rectifier by a linear active switching mode and feeding a supply voltage to the high frequency oscillator. With such configuration, the electronic ballast can be combined with a conventional thyristor lighting controller.

US Patent:

6739737, May 25, 2004

Filed:

Jun 21, 2002

Appl. No.:

10/175807

Inventors:

William Yu - Laytonsville MD 20882

International Classification:

F21V 700

US Classification:

362300, 362246, 362260, 362297, 313634, 313116

Abstract:

A lamp body of the compact spot and flood light type suitable for use with a compact fluorescent light source, wherein the lamp body includes a lamp head, a lampshade for reflecting the light emitted from the light source, and an adapter connected to the lamp head, wherein the lampshade is formed by the integration of at least two coaxial conical surfaces with different vertex angles.

US Patent:

7256539, Aug 14, 2007

Filed:

Jan 7, 2003

Appl. No.:

10/500850

Inventors:

William Yu - Laytonsville MD, US

International Classification:

H01J 63/04
H01J 5/48
H01J 5/50
H01J 5/54
F21V 7/10
H01R 33/08

US Classification:

313493, 31331802, 362216, 362260, 439242, 439617

Abstract:

An eccentric planar fluorescent tube includes an outer planar fluorescent tubular member that extends substantially but not completely about a center point and which is extended by two inner portions that extend from a first peripheral portion of the outer tubular member and on opposite sides of the center point and terminate at ends proximate to an opposite peripheral portion of the outer tubular member and wherein the ends are connected by a leg member for supplying power to the fluorescent tube. In one embodiment, the leg member includes electrical contacts that extend substantially in a plane of the outer tubular member and, in another embodiment, a central adapter may be provided including electrical contacts that extend transversely with respect to the plane of the outer tubular member.

US Patent:

7520072, Apr 21, 2009

Filed:

May 9, 2007

Appl. No.:

11/798033

Inventors:

William Yu - Laytonsville MD, US

International Classification:

G09F 13/04

US Classification:

40570, 362 20, 307 66, 315 86

Abstract:

Emergency signs and combination emergency signs and emergency lights wherein the combination signs are compact for shipment and are energy efficient using first interior light emitting diodes, powered by an AC power source, for illumination of messages formed in at least one side wall of the emergency signs and having at least one emergency light emitting diode lamp for providing emergency lighting in the event of AC power failure and wherein the at least one emergency light emitting diode lamp, in some embodiments, is selectively deployable and adjustable relative to the signs, and in others, is fixedly mounted relative to the signs.

US Patent:

20100248401, Sep 30, 2010

Filed:

Feb 18, 2010

Appl. No.:

12/708377

Inventors:

William YU - Laytonsville MD, US

International Classification:

H01L 21/66
H01L 33/00

US Classification:

438 17, 438 28, 257E21531, 257E33055

Abstract:

A method for forming a light source by plurality of light-emitting units, includes: step (A), determining the number of the light-emitting units based on following factors: the factors include a maximum supply voltage of a power supply circuit and a working voltage of each of the light-emitting units; step (B), determining a set power of each of the light-emitting units based on a set power of the light source and the number of the light-emitting units determined in the step (A); step (C), fabricating or selecting each of the light-emitting units based on the working voltage of each of the light emitting units and the set power of each of the light-emitting units determined in the step (B); step D), forming the light source by connecting each of the light-emitting units obtained in the step (C) in series according to the number of the light-emitting units determined in the step (A). For the light source formed as the above method, the high efficient power supply with the maximum output voltage, to the light source load, can be realized and the same power supply circuit can supply power to the light source with different set power with maximum supply efficiency.

US Patent:

20110001150, Jan 6, 2011

Filed:

Jul 7, 2008

Appl. No.:

12/452514

Inventors:

William Yu - Laytonsville MD, US

International Classification:

H01L 33/52
H01L 33/62

US Classification:

257 98, 438 26, 438 29, 257 99, 257E33059, 257E33066, 257E33061

Abstract:

The present invention provides a light-emitting diode (LED) and a method for manufacturing said LED. The LED is characterized that, the silica gel as the interlayer is provided between the transparent organic material and the chip. The method for manufacturing is characterized that, a gel applying step for applying the silica gel and the solidifying step for solidifying the semi-finished product of LED applied with the silica gel are included prior to the material packaging step for packaging using the transparent organic material. The LED of this invention and the LED manufactured by the method of this invention have no light decay for the low-power, such as Ø5 mm or less LED, and little light decay for the high-power LED, and have the advantages of excellent weathering resistance and low production cost.

US Patent:

20110074372, Mar 31, 2011

Filed:

Feb 18, 2010

Appl. No.:

12/708399

Inventors:

William YU - Laytonsville MD, US

International Classification:

G05F 1/618

US Classification:

323282

Abstract:

An improved architecture of a power supply circuit with power factor correction, the power supply circuit includes power supply circuit output terminals and a voltage negative feedback circuit, the power supply circuit output terminals include a high potential terminals and a low potential terminals, the voltage negative feedback circuit includes a first feedback circuit and a second feedback circuit connected in series in order from the high potential terminal to the low potential terminal, a connection point of the first feedback circuit and the second feedback circuit acts as a feedback signal output terminal through which the voltage negative feedback circuit outputs a feedback signal, in the improved architecture, the first feedback circuit is replaced by a light source branch including a constant-current light source, and the second feedback circuit is replaced by a resistor branch for determining a working current of the light source branch. This improved architecture can perform a constant-current supply with high power factor and high efficiency for the light source.