Nisa Khan

Published: Nov 25, 2013 by Seeking Alpha (A leading financial website for investors)
Authors: Dr. Nisa Khan
Subjects: Information Technology

This article describes why Apple and Samsung remains as big winners despite their ongoing litigation battle against each other, while investors get the short end of the stick. But there are still opportunities to make money with such big, established companies if investors follow certain strategies to pick the right type of securities.

Published: Nov 18, 2013 by Seeking Alpha (A leading financial website for investors)
Authors: Dr. Nisa Khan
Subjects: Computer Science & Engineering

The article describes the investment opportunities and challenges in the LED display and lighting industries.

Published: Nov 11, 2013 by Seeking Alpha (A leading financial website for investors)
Authors: Dr. Nisa Khan
Subjects: Computer Science & Engineering

The article describes the dominance and weaknesses of Apple and Samsung's smartphone and tablet products. It further gives insights to what lies ahead for these companies in terms of where they might invest their large sums of cash to stay ahead of the competition in the communication, display and consequently LED lighting industries.

Published: Nov 01, 2013 by Seeking Alpha (A well recognized financial website for investors)
Authors: Dr. Nisa Khan
Subjects: Engineering - Electrical

The article describes the current and projected usage and market penetration of LEDs and OLEDs in the display and lighting industries. It explains the difference between LEDs and OLEDs as well as their benefits and challenges in scientific but nevertheless easy-to-understand terms.

By: Nisa Khan
Subjects: Engineering - Electrical

The optoelectronics industry developed LEDs to be used for lighting.  It solved such initial challenges as low efficacy (lumen/W)and poor "white light" color quality in LED lamps.  However, two important remaining problems for LED lamps are pronounced glare and inadequate diffusion of light over larger space.  My book, "Understanding LED Illumination" explains for the first time why LEDs in their present form have glare; the book also introduces novel techniques to diffuse light over broad space to create omni-directional and multi-directional light distribution.  Introductory descriptions of these are given in my LED Update column in Signs of the Times magazine:

http://www.nxtbook.com/nxtbooks/STMG/sott_201312/#/30

By: Nisa Khan

Dr. Khan recommends readers to read about her motivation, which is described in her LED Update column in the April 2013 issue of Signs of the Times magazine.  You can find this article here: http://www.nxtbook.com/nxtbooks/STMG/sott_201304/index.php?startid=28

By: Nisa Khan

Patent Abstract: 

Concepts for increasing brightness and uniformity and providing dimming for LED-illuminated signs and display are disclosed.  Substantial increase in brightness is achieved via reducing the distance between LED modules and the sign or display they illuminate by placing the LEDs on a raised grid platform constructed with a plurality of intersecting plates.  Whenever two plates intersect, a “grid-node” is formed, creating a plurality of intersections and grid nodes in a two-dimensional array.  On each grid-node, two distinct and electrically isolated LED sub-modules are placed.  By connecting all LED sub-modules parallel to one dimension (e.g., X-axis) in one series, and all LED sub-modules parallel to the other dimension (e.g., Y-axis) in another series, two electrically isolated LED series are created.  Lighting up both series provide maximum brightness and good uniformity; lighting up only one series allows dimming for illuminated signs or displays without any drive current adjustment.

By: Nisa Khan
Subjects: Engineering - Electrical

Patent Abstract:  An LED replacement-lamp design concept comprising tapered waveguides to provide uniform and broad light distribution is disclosed. Currently, most LED-based replacement lamps for tubular fluorescent lamps place discrete surface-mount LEDs directly on a cylindrical base, which produce wasteful, non-uniform and directional illumination unsuitable for large space and high-ceiling applications.  An LED lamp design, proposed as a tubular lamp replacement, comprises of a plurality of discrete LEDs mounted on a common substrate, where all light from each LED is immediately guided and broadened through a tapered waveguide long enough to seamlessly terminate at the lamp’s semi-circularly curved cover surface.  Many such LED-waveguide assemblies can fill the entire curved cover with diffused and uniform light distribution, resulting in illumination over broad angular ranges.  The proposed lamp has a “D” shaped cross-section wherein the lamp’s flat side is used as a heat-sink base to be placed against the ceiling or some blocking surface.