Issue 031 Cover

Solid State Lighting

By Khaled Abou Alfa • 29th of July, 2020

In 1927, Oleg Losev, a Russian inventor and scientist would introduce the world to the light-emitting diode. This technology would remain dormant for decades. Progress was made in 1962 with the introduction of the first red LED. For the next 30 years, an industry would hunt for the elusive colour blue. Over time the risk of pouring resource and treasure into this pursuit increased - you were chasing the pot of gold at the end of a blue coloured rainbow.

These pursuits would continue with little success until the early 90s. Then the work of Shuji Nakamura, Isamu Akosaki and Hiroshi Amano unlocked the secrets of the blue LED. So significant was this discovery that in 2004, the trio would receive the Nobel price in Physics.

This work would be employed in diverse contexts, from the multitude of screens we depend upon to data communications. For the built environment, this discovery would transform artificial lighting across the world. The incandescent (and to a lesser extent the fluorescent) lamp illuminated the 20th century. Light for the 21st century would be ushered in by the LED lamp.

Obsolete Lighting Law

In 1999, Roland Haitz co-authored a research report, on the future of LED lighting (which was renamed as solid state lighting). The paper included data collected over decades that plotted both the cost of lumens and the red light output per LED package since the 1970s. 20 years ago Haitz empirically predicted the world we are living in today and captured in a law’ which states:

Every decade, for a given wavelength of light, the cost per lumen falls by a factor of 10 and the amount of light generated per LED package increases by a factor of 20.
— Haitz’s Law

A new report, which addressed the shortcomings and reviewed the impact of the earlier report, was published a decade later in 2010. This paper predicted that within the decade (by 2020), we would have reached a point of diminishing returns. It acknowledged that Solid State Lighting (SSL) is limited in two areas. The conversion efficacy - converting electrical energy to luminous flux cannot exceed 100%. The actual need for increased flux range - just because you can produce it, doesn’t mean the market needs it. The paper provided indications of where the future after 2020 is likely to evolve:

These include digital tuning of both the chromaticity and the temporal/spatial placement of light within the environment that is being lit.’

27 years after the initial spark of the blue LED revolution, we are now entering a period of equilibrium of both the efficacy and flux of solid state lighting. The advances in lighting have now begun to shift into new territory, one of circadian rhythms, diurnal patterns and refined controllability.


Inline with the predictions from 10 years ago, the lighting industry has begun to focus its attention on how SSL can be controlled and manipulated. The technology available today would be considered both technically impossible and prohibitively expensive, compared with technology from only 15 years ago.

The terms circadian lighting’ or human centric lighting’ have begun entering the lexicon as a means to enhance the wellbeing of everyone interacting with the built world. With the advent of SSL technology we are now able to control parameters such as colour spectrum, intensity and directionality. These systems offer control based on the exact location, the relationship to the outside world and what is happening outside in real time.

The main debate for the use of this type of lighting control is whether it actually works. Does it suppress the levels of Melatonin in the body? Does it make people more alert and therefore more responsive throughout the day? These are some of the questions that the industry will need to address for the technology to become more widespread.

In the last two decades, the lighting industry has experienced a revolution. This has led to an expanded scope of what is achievable with light in a manner unimaginable back in 1927. Incredibly these benefits have come at a greatly reduced level of energy consumption (typically 1/5th of previous technologies). The work is far from done, as incandecent lamp sources (amongst others) remain in wide use throughout the world (global penetration of LEDs hovers around 61%). We must wean ourselves both for our own wellbeing and that of the planet.


Dyson’s Car


We now know what form factor Dyson had chosen for their now shelved electric vehicle. Micromobility this is not.

The Dyson’s interview demonstrates the tone deaf nature associated with cars. You may need a car for some activities, but for most of your mobility needs, you likely can get away with other methods. How different our cities would be if we could understand and embrace that reality together.

In adjacent news the guys over at have been documenting our transition for a while. Just released is version 2.0 of their Landscape document. The document demonstrates the breadth that is on offer in this field.

Wide Timber


The 2020 Tokyo Olympics may have been postponed but that doesn’t mean we don’t get to marvel at some stunning timber architecture. As covered in issue 007, the Japanese know a thing or two about building in timber. The completion of the Ariake gymnastics center is a wonderful extension of that history.


Tools of the Trade

Spoke Pens

Spoke Pens

Over the past 5–10 years there has been an incredible industry of machined pens produced and sold on Kickstarter. I have found that the ergonomic design and available refill options to be under-represented. Rather than focusing on the utility of the pen itself, many focus on both the materials and aesthetic design instead.

Most people make the mistake of thinking design is what it looks like. People think it’s this veneer — that the designers are handed this box and told, Make it look good!” That’s not what we think design is. It’s not just what it looks like and feels like. Design is how it works.
— Steve Jobs

In this regard, the Spoke pens and pencils are different. The inside was considered first - even though the outside has a strong design language. The pen is primarily a wrap around the pen refill or pencil mechanism. The pens accept the standard Muji Gel ink refills or the Uni Signo DX refills (both come in a range of colours and go down to the 0.38mm range). While the pencil is based on the Pentel P20# mechanical pencil mechanism. Both are highly recommended.

The Stet newsletter explores the ideas, projects and technologies that define our built environment.