Project

Why Inorganic LEDs have Inherent Glare and Extremely High Luminance

Goal: It is surprising as well as disheartening that after almost 4 years of my book, “Understanding LED Illumination (CRC Press, 2013)” being out there, no one has caught on why inorganic LEDs and lasers have glare and extremely high luminance by nature – a fundamental phenomenon I have discovered and explained in my book. The book was also reviewed by several university professors, none of whom, I believe understood the explanation I have provided in the book on why inorganic, semiconductor LEDs inherently have high luminance and therefore glare. I have explained this further with simulations and other scientific findings in other published articles since the book – and yet only a few people who understood the phenomenon are those that needed my personal explanations on the physics and mathematical derivation used to explain the phenomenon. Sadly the whole world is still vigorously moving towards replacing incumbent lighting products with LED counterparts despite the fact that incumbent lighting products do not have such high luminance or glare. Why haven't those involved in academia and esteemed research in notable corporations taken an interest in understanding what I have said in my publications? Why are corporations wasting multi-billion USD in making LED lighting products that have blinding glare and unfit spatial light distributions for illumination purposes? Why are people overlooking my work, the help I offered, and recommendations? Can the scientific and engineering research community come to the rescue on this extremely important issue, which stands to blind us and ruin our health and ecology if we don’t?

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M. Nisa Khan
added a project goal
It is surprising as well as disheartening that after almost 4 years of my book, “Understanding LED Illumination (CRC Press, 2013)” being out there, no one has caught on why inorganic LEDs and lasers have glare and extremely high luminance by nature – a fundamental phenomenon I have discovered and explained in my book. The book was also reviewed by several university professors, none of whom, I believe understood the explanation I have provided in the book on why inorganic, semiconductor LEDs inherently have high luminance and therefore glare. I have explained this further with simulations and other scientific findings in other published articles since the book – and yet only a few people who understood the phenomenon are those that needed my personal explanations on the physics and mathematical derivation used to explain the phenomenon. Sadly the whole world is still vigorously moving towards replacing incumbent lighting products with LED counterparts despite the fact that incumbent lighting products do not have such high luminance or glare. Why haven't those involved in academia and esteemed research in notable corporations taken an interest in understanding what I have said in my publications? Why are corporations wasting multi-billion USD in making LED lighting products that have blinding glare and unfit spatial light distributions for illumination purposes? Why are people overlooking my work, the help I offered, and recommendations? Can the scientific and engineering research community come to the rescue on this extremely important issue, which stands to blind us and ruin our health and ecology if we don’t?
 
M. Nisa Khan
added a research item
Testimonies from LED lighting sufferers are presented. For existing research studies, the readers should look at the archives from National Library of Medicine.
M. Nisa Khan
added a research item
I am writing this letter on behalf of Marie Johnson who is suffering epileptic seizures when exposed to LED lights. Light Emitting Diodes emit light from a flat chip, causing the cones of light to overlap which creates a spatial light distribution profile that overloads Marie's central nervous system. The purpose of this letter is to explain why LEDs are not safe for lighting large living spaces. Marie and many more like her who are light sensitive are debilitated when exposed to LED streetlights, LED vehicle lights and many other types of LED lights that unfortunately became ubiquitous in public places without government agencies conducting proper health studies and without the consent of the general public and residents in communities. Despite the fact that the lighting and optics industries have either misunderstood or purposely ignored the inconvenient mathematics and science of LEDs, LED lighting is increasingly replacing nearly all legacy lighting with the erroneous claim that they are more efficient compared to legacy lighting. LED streetlights do not save any appreciable amount of energy compared to modern high-pressure sodium and low-pressure sodium streetlights when recognizing that light from an LED is a directed-beam that produces very poor quality illumination [1]. The lighting produced by LEDs is poor because it produces too much light power in the middle of the lamp and along its center directional path while producing inadequate light power outside this narrow cone of directive light. The spectrum of LED lights is also unnatural causing further damage to our vision and general health. I am an optics and lighting scientist as well as an engineer and a mathematician by training and I have worked in the field of optics, lighting and communication science and engineering for over 35 years. I was the first person to describe in a peer-reviewed scientific paper [2] how LED light distribution in space is entirely different compared to light generated from a spherical source. My reason for writing to you is to clarify why and how illumination from an LED-based lamp is of poor quality and why inorganic LEDs are not suited for large volumetric space illumination as required for streetlights and vehicle headlights. While low-luminance LEDs are suitable for indicator lights such as exit signs and displays, this exact natural suitability for illuminating flat surfaces is the very reason why they are not appropriate for illuminating streets, warehouses, stadium arenas, and other spaces that are by nature volumetric regions that provide living spaces for us and other species. The very nature of illumination of these
M. Nisa Khan
added an update
I have now published a peer-reviewed paper in the IEEE Photonics Journal that demonstrates why flat LED light sources produce a Lambertian light intensity distribution and why such light intensity distribution produces directive light with intensity peak along its center optic axis.
You can find this open access paper here:
While my last paper was rejected by peer-reviewers from OSA, AIP, and Japan OS journals with horrendously erroneous reviews, this paper now shows why my derivations are correct and what it means for high-power and high intensity LED lamps such as those in LED car headlamps.
I urge the car headlight standard bodies to really think through what I have written in the paper that I independently published in ResearchGate and this peer-reviewed paper. My work is novel and has significant impact in cautioning why high-power and high intensity LEDs and their 2D arrays should not be used as lamps as they are very dangerous for our eyes. More research must be done to find suitable LED lamps for car and street light applications and until then we should ban them from being deployed.
As a proper design, my patented design offers the only way to diffuse light properly from LED light sources. Any other secondary optics for diffusing LED and laser light is ineffective and Fourier Optics proves this case.
 
M. Nisa Khan
added a research item
We derive the near-field light intensity distributions of an inorganic LED on its surface and in volumetric space. Our closed-form solution for 3D intensity distribution for a finite-size LED is consistent with Lambert’s Cosine Law, which provides the 3D intensity distribution for an infinitesimal, flat light source. We also derive the formula for the 2D intensity distribution on a diode surface showing its similarity to a Gaussian function, which is typically used to approximate the surface light intensity profile for an LED and a laser diode. Our 2D intensity distribution function produces light propagation similar to the Gaussian beam propagation in space. However, unlike the Gaussian approximation, our formula invariably produces this behavior without assuming the refractive index inside the diode follows a quadratic function of the transverse spatial domains. Our 2D and 3D spatial intensity formulas in near-field for LEDs offer a unique way to calculate the peak intensity that occurs at the center of the flat LED source. We demonstrate, as expected, that the peak intensity increases with the size of the LED source as well as the brightness of each radiative electron-hole pair, which is a function of the drive current and quantum efficiency of the LED.
M. Nisa Khan
added 2 research items
Glare and blue light from LED-based lamps have raised great concerns for medical professionals around the world. Addressing them requires accurate quantification of luminous intensity distribution (LID) generated by LEDs. For the first time, we demonstrate why inorganic LED chips including a phosphor coating produce non-uniform luminance, high peak luminance, high glare, and very intense blue spectrum. We explain why flat light-emitting devices generate a 3D Lambertian LID in near-field, and offer a novel formulation of the near-field LID from a finite-size flat-light source. Our analytic formula, extendable for lasers, is very useful for calculating the peak luminance and LID profiles from an LED light source. It reveals that larger LED chips and 2D arrays with higher luminance generate higher peak luminance, higher luminous intensity, and increased glare and can result in consuming unsafe amounts of bright light and harmful blue light when we directly look at high-power LED lamps. © 2019 Independently published by M. Nisa Khan. (This article was rejected by OSA and other scientific journals. The reviewers' erroneous reviews and my rebuttals are also published independently by Khan.)
The paper added here is the same paper I published in ResearchGate. The reader should know that this paper was peer-reviewed many, many times and rejected because the peer-reviewers don't understand advanced calculus, analytic geometry and photometric parameters such as luminance and luminous intensity. I have also provided 8 rebuttal documents of all the erroneous peer-reviews I received on this manuscript. These can all be found in this project in ResearchGate.
M. Nisa Khan
added a research item
This document is a continuation of Part I through Part VI published on June 3, 2019, June 5, 2019, June 10, June 12, June 17 and June 21, 2019 respectively. The prior parts contained the reviews from 3 OSA Journals where OSA's Applied Optics reviewed my paper twice, and Optical Review by the Japanese Optical Society, for which I provided comprehensive rebuttals for each erroneous review from all the reviewers and editors. This document contains the first reviews from the manuscript I submitted to Journal of Applied Physics (JAP), which was the very first version of my paper that was entitled as shown above. Note that this title is slightly different from the titles of those versions submitted to other journals. However, the core material in all the versions of my paper is the same. Six weeks after my submission, JAP Editorial Office alerted me with an apology saying they were having difficulties in finding the mandatory number of reviewers for my paper. Shortly after, they sent reviews from two reviewers that totally baffled me as they were not only erroneous-but that the reviewers didn't even have the very basic knowledge of optical physics and calculus. I was shocked for the first time in my scientific career about how physics Ph.D.'s could be so ignorant about basic physics and mathematics and how they could be so sure that I didn't have anything important to say leading them to conclude I was simply worthless for the scientific community. Among the many fundamentals the reviewers missed are their lack of knowledge between a finite and an infinitesimal source; what Maxwell's Equation and Gauss' Divergence Theorem say in plain English; and the difference between the 2D light distribution that a laser or LED produces on its surface versus what 3D light distribution they produce in the near-field space. I ask the readers from all disciplines to judge what they wrote in the reviews against my manuscript. I ask the serious scientists and mathematicians to read my rebuttals against their objections to my paper and decide for themselves whether my work is valid and beneficial. If they decide that my work is valid and beneficial, perhaps an academic town hall meeting should be arranged among notable physicists, mathematicians and electrical engineers to debate and discuss my contribution to how light emission occurs from solid-state devices. I am personally eager to participate in such meeting where I would go to the white board to derive and demonstrate that all I have presented in my paper is valid and beneficial; and my derivation of the near-field light intensity from inorganic LEDs is novel, which unfortunately was missed by many notable laser and optical scientists for many decades. Copyrighted by M. Nisa Khan ©
M. Nisa Khan
added a research item
This document is a continuation of Part I through Part V published on June 3, 2019, June 5, 2019, June 10, June 12, and June 17, 2019 respectively. The prior parts contained the reviews from 3 OSA Journals, and Optical Review by the Japanese Optical Society for which I provided comprehensive rebuttals for each erroneous review from the reviewers and editors. Note that the title of the second paper submitted to Applied Optics as stated above is slightly different from those versions submitted to other journals. However, the core material in all the versions of my paper is the same. This document contains the 3rd review from my first Applied Optics submission and the two reviews I received from my second manuscript submission to Applied Optics by OSA Publishing back in October 5, 2018, over the course of two and half months. The Editor-in-Chief, Dr. Ron Driggers again chose the same Topical Editor, Dr. Libo Yuan for my second submission. It is likely that 2 of the reviewers are the same for both submissions and they really don’t have any knowledge or background in calculus in spherical coordinates, what Maxwell’s Equations really mean, what boundary conditions apply to lightwaves in different media, and finally what lighting science is all about. My rebuttals against the erroneous reviews establish what I have stated here.
M. Nisa Khan
added a research item
This document is a continuation of Part I through Part IV published on June 3, 2019, June 5, 2019, June 10, and June 12, 2019 respectively. The prior parts contained the reviews from 3 OSA Journals, and Optical Review by the Japanese Optical Society for which I provided comprehensive rebuttals for each erroneous review from the reviewers and editors. Note that the title of the first paper submitted to Applied Optics as stated above is slightly different from those versions submitted to other journals. However, the core material in all the versions of my paper is the same. This document contains the very first review I received from Applied Optics by OSA Publishing back in January 28, 2018, after a long 3 months. Here I present the exact review in its entirety: “Reviewer 1: I have any advice for this manuscript. However, this manuscript has not show any novel idea.” The poor English aside, it struck me as odd that this is the review I would receive after 3 long months from Applied Optics. This article also contains 2 other reviews I received from Applied Optics after this precious review and my rebuttals follow each of the erroneous reviews. It is abundantly clear that those in the optics community that make up OSA Publishing and the rest of the academic and industrial optics community really have no idea what lighting fundamentals are. Unfortunately, the lighting community does not either. The lighting community got away with such deficiency because the incandescent and gas-discharge manufacturers gave them lamps that already had perfect luminance distributions and therefore effective diffusing characteristics in space. However, in order to understand LED lighting, current optics and lighting communities must learn what luminance and luminous intensity really are and what they mean for lighting. Simply knowing their definitions and units are not sufficient. I welcome the excellent physics and mathematics professionals and academics around the world to look at my paper, the erroneous reviews and my rebuttals and come forward with their voice of reason in order to help ban the current LED streetlights and car headlights.
M. Nisa Khan
added a research item
This document contains the review from the Associate Editor of OSA Continuum Journal by OSA Publishing. The editor did not make an attempt to find any reviewers because he was convinced that I was wrong outright on a very basic mathematical problem. Sadly, his objection revealed he is very mistaken in the most basic understanding of calculus and spherical coordinates, much less than the understanding that is needed to do a 3D integral in spherical coordinates. He is also confused between what the angles, θ and φ , are in spherical coordinates and he provides a wrong result for the volume of a cone when he attempts to correct me. I continue to believe there are some people in the world, scientists and alike, do care about understanding why LED light is directional and why many of today's high-power and high-intensity LED lamps sting our eyes when we directly look at them or are viewing them from certain viewing angles off the center. The optics and lighting communities at large have shown no real interest in explaining this issue and many of them just deny that lighting quality is compromised in such LED lighting products. The deficiencies in understanding optics and lighting comprehensively have led to dangerous LED streetlights and auto headlights, as well as reviewers failing to understand and appreciate what I presented in my manuscript.
M. Nisa Khan
added a research item
The Optical Review Journal is by Springer and it iss overseen by Japanese optical scientists and researchers. Note that the paper this journal reviewed has a slightly different title; however, the content of this paper I wrote is essentially the same as that reviewed by OSA Journals. The reviews I received from Optical Review are also disturbingly invalid. Furthermore, this review process took six months to review my paper, after which I received erroneous reviews from two reviewers. Here I present the reviewers' erroneous objections and my rebuttals against these objections. I found the reviews disturbing because these reviewers unfortunately lack basic knowledge in lighting and in guided-wave optics, which are vital for understanding LED lighting. The reviewers sadly lack the knowledge of how optical waveguides work and why lasers and LEDs are designed with certain p and n layers to achieve waveguiding effects for desirable light confinement. It is sad that so many people working on optoelectronic materials and devices fail to see why double hetero-structure using semiconductor materials are utilized to lower lasing threshold and increase lasing efficiency. These ideas are directly transferred to create high-efficiency LEDs. The reviewers lack the knowledge that connects light generation in semiconductor diodes to how light must be manipulated by design to achieve light confinement in active layers, which then needs to escape out of LEDs and lasers in a desirable manner. It has been decades since optical waveguide theory, design, and implementation have been utilized and yet thousands of optical scientists working on LEDs and lasers are in the dark about light generation, confinement and extraction, and propagation-which ALL work based on Maxwell's Equations, optical boundary conditions in media and their interfaces. What a tragedy! The deficiencies in understanding optics and lighting comprehensively have led to dangerous LED streetlights and auto headlights, as well as reviewers failing to understand and appreciate what I presented in my manuscript. This article shows why the reviewers from Optics Review are mistaken in each and every single objection they had for my manuscript.-Dr. M. Nisa Khan. Copyrighted by M. Nisa Khan ©
M. Nisa Khan
added a research item
This document is a continuation of Part I published on June 3, 2014. Part I contained the reviews from 2 OSA Journals for which I provided comprehensive rebuttals for each erroneous review from the reviewers and the Editor-in-Chief from OSA Continuum. Since I found those reviews to be disturbingly invalid, I decided to submit my manuscript to Optics Express with my rebuttal explanations submitted as "Authors Response" as required by the OSA Journal peer-review process. The review process by Optics Express chose one reviewer to review my manuscript. Here I present this reviewer's erroneous objections and my rebuttals against these objections. I found the reviews from this person particularly disturbing because it is abundantly clear that he lacks basic knowledge in lighting, integral calculus in spherical coordinates, and many necessary disciplines within the field of optics that are vital for understanding LED lighting. His background is very likely in secondary optics that attends to manipulating light beams for non-lighting applications. For many years, I have cautioned that optics professionals, working on LED lighting while lacking a lighting background, is very worrisome. Reciprocally, lighting professionals working on LED lighting while lacking the knowledge of optics and lighting science along with mathematics that support them comprehensively, is also very troubling. These deficiencies still exist today resulting in dangerous LED streetlights and auto headlights, as well as reviewers failing to understand and appreciate what I presented in my manuscript. This article shows why the reviewer from Optics Express is mistaken in each and every single objection he had for my manuscript.-Dr. M. Nisa Khan. Copyrighted by M. Nisa Khan ©-******-Before I present the reviews I received on May 23, 2019 from the Editor-in-Chief of Optics Express, I would like to express my general position on this review. The reviewer appears to not have any appreciation that lighting has its own appropriate parameters, and that acceptable range of values for these parameters must be in place for a light source to be a decent lighting source. (Although I do not know the reviewer, for reading ease, I shall use the pronoun, 'he' in this article.) I say this with a great deal of confidence because he failed to follow the valid physics and mathematics in my paper with respect inherent problems that LEDs and laser have in order to be used for lighting. Further, he believes that secondary optics, such as lenses and baffles, can alter the behavior of a Lambertian distribution substantially in order to properly diffuse the light from an LED or a 2D arrayed-ensemble of LEDs. A misunderstanding of this kind demonstrates that the reviewer is not familiar with Fourier optics and guided-wave optics-the two optics fields that are crucial to understanding that a flat LED of the kind used for LED lamps produces a light distribution on the LED surface that resembles a Gaussian, which in turn is related to the Lambertian light intensity distribution (LID) it produces in 3D near-field. Someone
M. Nisa Khan
added a research item
Here I present the reviews and rebuttals I received from a number of OSA journals over the course of nearly 2 years. There will be more to come regarding other reviews I received and my rebuttals against them. I have given OSA editors and reviewers plenty of opportunities to correct themselves, go back to the university-level physics and calculus textbooks and think through what Maxwell's Equations and Divergence Theorem really say in plain English and what a Lambertian light distribution really means for lighting. They all failed to do so. So now these will all be presented in the media and I welcome excellent mathematicians and physicists, like those I had at Macalester College, to read through my paper, the erroneous reviews and my rebuttals against them, to understand how dangerous high-power and high-intensity certain LED lamps are, such as those in today's auto headlamps and streetlamps. Surely, the math and physics theory established by Gauss, Fourier, Faraday, Maxwell and Einstein were not all for nothing. As scientists and mathematicians, we are to really learn from them and only adopt products and technologies that don't stand to ruin our eyes, health, ecology, and the environment. I have faith that somebody like Walter Pitts is out there to pick up on my work on LED lighting and tell the wider audience that I have in fact shown, with a great deal of scientific rigor, why LED lighting is unsuitable and dangerous for us, unless the Lambertian distribution is sufficiently destroyed to make light emission from flat LEDs substantially radially symmetric.-Dr. M.
M. Nisa Khan
added a research item
Glare and blue light from LED-based lamps have raised great concerns for medical professionals around the world. Addressing them requires accurate quantification of luminous intensity distribution (LID) generated by LEDs. For the first time, we demonstrate why inorganic LED chips including a phosphor coating produce non-uniform luminance, high peak luminance, high glare, and very intense blue spectrum. We explain why flat light-emitting devices generate a 3D Lambertian LID in near-field, and offer a novel formulation of the near-field LID from a finite-size flat-light source. Our analytic formula, extendable for lasers, is very useful for calculating the peak luminance and LID profiles from an LED light source. It reveals that larger LED chips and 2D arrays with higher luminance generate higher peak luminance, higher luminous intensity, and increased glare and can result in consuming unsafe amounts of bright light and harmful blue light when we directly look at high-power LED lamps. © 2019 Independently published by M. Nisa Khan. (This article was rejected by OSA and other scientific journals. The reviewers' erroneous reviews and my rebuttals are also published independently by Khan.)
M. Nisa Khan
added an update
I have been writing about why LEDs inherently have tremendous luminance and therefore glare. It is unfortunate that some in the technical community still don't see why flat light emitting devices made in inorganic semiconductors inherently produce tremendous luminance, especially along the center optic axis. Those who are still not seeing what I am saying, please watch this recent news piece where regular people are asking LED headlamps in cars to be banned and that at least powers that be should investigate this. I can help with this investigation. Here is the video clip of the news:
Please contact me if you need scientific explanations for this problem. The optics community must pay attention to this as soon as possible.
 
M. Nisa Khan
added a research item
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.
M. Nisa Khan
added an update
At this time, I assert that an inorganic LED or laser chip is not a point source as defined in physics. I also assert that LED-based current luminaires do not produce spatial light distribution or luminous intensity distribution (LID) similar to other light sources such as gas-discharge and incandescent lamps. The lighting and LED lighting industry continue to insist that LED luminaires' LID is about the same as other lamps while the vast majority of LED luminaires deployed for road lighting are clearly showing that it is not the case. Meanwhile we have either over or under illumination in roads and in other outdoor places with LED luminaires and that is far from the good light distribution we receive from gas-discharge based lamps.
 
M. Nisa Khan
added an update
Interested academics and researchers are encouraged to contact me in person with questions and comments on this project. It is vital that we publicize the understanding of LED's inherent glare and the reasons for their inherent Lambertian spatial light distribution and why these factors make current solid-state lighting dangerous and unfit for lighitng purposes.