Kenneth S Li

US Patent:

6385371, May 7, 2002

Filed:

Apr 3, 2000

Appl. No.:

09/541516

Inventors:

Kenneth K. Li - Arcadia CA

Assignee:

Cogent Light Technologies, Inc. - Santa Clarita CA

International Classification:

G02B 604

US Classification:

385 43, 385121, 385 47

Abstract:

An optical system includes a coupling for transmitting light between one single fiber light guide and multiple single fiber light guides. The interface surfaces coupling the single fiber light guide to the multiple light guides have polygonal cross-sectional shapes, and the interface surface of the single fiber light guide is substantially covered by the interface surfaces of the multiple single fiber light guides. The single fiber light guide on one side of the coupling and the multiple single fiber light guides on the opposite side of the coupling each have a smoothly tapered contracting section extending away from the respective interface surfaces.

US Patent:

6496620, Dec 17, 2002

Filed:

Apr 21, 1999

Appl. No.:

09/295379

Inventors:

Chingfa Chen - West Covina CA
Kenneth K. Li - Arcadia CA
Douglas M. Brenner - Los Angeles CA

Assignee:

Wavien, Inc. - Santa Clara CA

International Classification:

G02B 626

US Classification:

385 31

Abstract:

The power handling capability of polymer fibers is increased by broadening an input intensity profile, which is typically Gaussian, without significantly decreasing the efficiency of coupling light into a polymer fiber. The method for increasing the power handling capability of polymer fibers includes the steps of: a) emitting light having a Gaussian intensity profile from a fiber light source; b) broadening the Gaussian intensity profile so that energy at the center of the Gaussian intensity profile is distributed to the perimeter to reduce the peak power intensity of the emitted light before it is launched into the polymer fiber; c) transmitting the emitted light into at least one polymer fiber. Preferably, a fused bundle is used to broaden the intensity profile and preferably the fused bundle has an angled input end face. As a result, more total power can be coupled into the polymer fiber while keeping below the melting threshold caused by the light absorptionâenabling, for example, power in excess of 1 Watt to be transmitted through a 1-mm diameter PMMA fiber.

US Patent:

6565235, May 20, 2003

Filed:

Oct 23, 2001

Appl. No.:

09/983213

Inventors:

Kenneth K. Li - Arcadia CA

Assignee:

Cogent Light Technologies Inc. - Santa Clarita CA

International Classification:

F21V 800

US Classification:

362304, 362305

Abstract:

An optical device for increasing the brightness of electromagnetic radiation emitted by a source by folding the electromagnetic radiation back on itself. The source of electromagnetic radiation has a first width, a first input end of a first light pipe has a second width, and a second input end of a second light pipe has a third width. An output end of the first light pipe may be reflective, while an output end of the second light pipe may be transmissive. The source is located substantially proximate to a first focal point of a first reflector to produce rays of radiation that reflect from the first reflector to a second reflector and substantially converge at a second focal point; and the input ends of the first and second light pipes are located proximate to the second focal point to collect the electromagnetic radiation.

US Patent:

6587269, Jul 1, 2003

Filed:

Mar 23, 2001

Appl. No.:

09/814970

Inventors:

Kenneth K. Li - Arcadia CA

Assignee:

Cogent Light Technologies Inc. - Santa Clarita CA

International Classification:

G02B 530

US Classification:

359497, 359487, 359494, 359495, 349 9, 353 20, 385 11

Abstract:

A waveguide polarization recovery system both polarizes the input light energy for use with an LCD imager and converts the polarity of unusable light energy to add to the illumination of the LCD imager. The compact polarization recovery waveguide system generally includes: (1) an input waveguide that provides non-polarized light energy into the system; (2) an output waveguide that receives polarized light energy from the system; (3) a polarized beam splitter that received the light energy from the input waveguide and transmits lights energy of a first polarization type and reflects light energy of a second polarization type, and (4) a wave plate that modifies the polarization of either the transmitted or reflected light energy. The polarization recovery system also generally includes one or more mirrors that are positioned as need to direct the transmitted and the reflected light energy to the output waveguide. The input and output waveguides may be shaped as needed by the projection system.

US Patent:

6595673, Jul 22, 2003

Filed:

Dec 20, 1999

Appl. No.:

09/468410

Inventors:

Ronald A. Ferrante - Castaic CA
Kenneth K. Li - Arcadia CA

Assignee:

Cogent Light Technologies, Inc. - Santa Clarita CA

International Classification:

F21V 704

US Classification:

362551, 362558

Abstract:

A fiber optic illumination system with increased power handling capabilities for low melting point fiber optics uses an optical homogenizer. Homogenizers of the present invention preferably comprise a rod with polygonal cross-section. The output intensity of the optical homogenizer is substantially uniform such that the output fiber optic will not be damaged by hot spots created by non-uniform intensity light.

US Patent:

6616304, Sep 9, 2003

Filed:

Oct 3, 2001

Appl. No.:

09/969031

Inventors:

Kenneth K. Li - Arcadia CA

Assignee:

Cogent Light Technologies, Inc. - Santa Clarita CA

International Classification:

F21V 706

US Classification:

362302, 362298, 362293

Abstract:

A temperature control system for a source of electromagnetic radiation, such as an arc lamp, in a collecting and condensing system including a first reflector having a first focal point and a first optical axis, and a second reflector having a second focal point and a second optical axis. The source may be located proximate to the first focal point of the first reflector to produce rays of radiation that reflect from the first reflector toward the second reflector and substantially converge at the second focal point. A sensor, such as a voltage or a temperature sensor, may be placed near the source, and produces an output which may be substantially proportional to an attribute of the source. A comparator compares the output to a predetermined value and produces a difference between the output and the predetermined value. A fan placed proximate to the source has an air flow to cool the source which may be substantially proportional to the difference between the output and the predetermined value if the output is greater than the predetermined value.

US Patent:

6619820, Sep 16, 2003

Filed:

Sep 20, 2001

Appl. No.:

09/955980

Inventors:

Kenneth K. Li - Arcadia CA

Assignee:

Cogent Light Technologies, Inc. - Santa Clarita CA

International Classification:

F21V 709

US Classification:

362302, 362299, 362305, 362551

Abstract:

An optical coupling element for use in large numerical aperture collecting and condensing systems. The optical coupling element includes a lens having a curved surface and a tapered light pipe. The curved surface reduces the angle of incidence of the light striking the input end of the optical coupling element such that the Fresnel reflection is greatly reduced. Electromagnetic radiation emitted by a source is collected and focused onto a target by positioning the source of electromagnetic radiation at a first focal point of a first reflector so that the source produces rays of radiation reflected from the first reflector that converge at a second focal point of the second reflector. The optical coupling element is positioned so that a center of the lens is substantially proximate with the second focal point of the second reflector and the curved surface is between the second reflector and the center. The converging rays of radiation reflected from the second reflector pass through the curved surface of the lens and reach the center.

US Patent:

6626582, Sep 30, 2003

Filed:

Feb 13, 2001

Appl. No.:

09/781551

Inventors:

Harry Farrar - Woodland Hills CA
Kenneth K. Li - Arcadia CA

Assignee:

Cogent Light Technologies, Inc. - Santa Clarita CA

International Classification:

G02B 636

US Classification:

385 53, 385 88, 385 92, 385 70, 385 58

Abstract:

The present invention provides a connector assembly comprising (1) a first adapter that releasably connects to light source and transmits optical energy received from the light source along a first optical waveguide; (2) a second adapter that releasably connects to first adapter to receive and transmit optical energy along a second optical waveguide; and (3) an output optical waveguide that receives the transmitted optical energy from the second waveguide and has a proximal connector adapted to fixedly engage the second adapter. In one embodiment, the proximal connector has a slot that allows for the insertion of a clip, and the second adapter has a detente that mechanically engages the clip when it is inserted into the slot in the proximal connector. In this way, the second adapter is fixedly coupled to the proximal connector but may also rotate in relation to the output connector. In one implementation, the groove in the adapter is angled so that an inserted clip presses against the angled surface, resulting in a force to urge and hold the second adapter into proper position for optical connection between the first optical waveguide and the output optical waveguide.