Controls in Space, Time, and Color




QuarkStar technologies are all about 'control' – whether controlling the distribution of light in Space or effecting desired changes in Time (and avoiding temporal changes like flicker). And Color must also be controlled at any given moment to optimize the use of light at that time, along with controlling the color output over the lifetime of the fixture.

QuarkStar technologies exist to deal with all of these aspects of control:
Controls in Space [top of page]
  • Edge-X, Advanced Light Source, and Light Sheet/Filament technologies all start with optimizing the use of etendue at the source and then apply sophisticated optics to create class-defining lighting distributions with previously unattainable uniformity. QuarkStar’s Edge-X™ can provide an unusually uniform luminance on across a plane, its optics capable of making better than a 4:1 gradient across a 10 foot plane (ceiling or wall).  
  • The ability of our optical designs to create such a uniform light with sharp cut-offs is proven and exemplified in the QuarkStar fixtures used as primary gallery artificial lighting in the newly built centerpiece building of the Museum of Fine Arts Houston. [See photos of the 16 foot walls at the MFAH.]
 
  • This is a high efficacy solution – optical control delivering light to the target surfaces and nowhere else. Precise control of light delivery without baffles also eliminates stray light and light trespass, thus maximizing the efficacy of light delivered to the target/work surface.  Light-on-target divided by light output is often 0.8, but with QuarkStar it is nearly 1.
 
  • Such things as glare are mitigated by several QuarkStar tech-based capabilities. The most important is the ability to precisely define distributions. Targeting precisely where light goes from a fixture helps avoid direct emission glare by avoiding emission in solid-angle ‘glare-zones’. The ability to eliminate angles contributing to glare is also evdent in QuarkStar’s MFAH fixtures.
 
  • Additional glare control comes from Edge-X’s unique ability to provide both direct and indirect distributions from a single optic a few mm wide. This is in addition to providing a pleasing, indirect source of light illumination of the ceiling increases background luminance. This is a critical capability because perceived glare decreases as the ratio between the luminance of the source and the luminance of the background decreases.
 
  • This control of perceived glare through QuarkStar’s high degree of spatial control also contributes to the unique scalability of its optics. Conventional optics when joined with solid-state sources doesn’t scale smaller very well due to the limitations of glare: i.e the smaller the output area, the higher the perceived luminosity coming from the scaled-down area… hence ‘perceived glare’.
 
  • But QuarkStar finesses this otherwise intractable problem by shaping the distribution of light as above, even from a single optic just a few mm wide. In consequence QuarkStar fixtures can be much smaller than others, with a footprint so small as to decrease manufacturing costs due to smaller material needs and the opportunity for new options of architectural integration.
 
Real World example
QuarkStar’s fixtures at the MFAH easily distribute sheets of uniform light spanning 16-ft gallery walls accompanied by daylight matching color-tuning from a single row of LEDs. And the footprint is all from an optic less than an inch wide! So when the museum saw it placed in a ceiling mockup, they chose to redesign the galleries to take advantage of the empty space that was left behind.  LD+A Issue May 2021


  • Edge-X patented designs also exist that allow real-time changes in lighting distributions, with samples having been shown at LightFair (contributing to QuarkStar winning the Lux Top 10 Products at LightFair award).
 
  • And all the above comes with the highest efficacies. There is no compromise necessary to provide the above spatial and glare controls while also having fixture efficacies > 90%, up to 96%.​
Controls in Time (Intensity, Distribution, Color) [top of page]
 
QuarkStar solutions include temporal control from both hardware and software implementations. Unique and patented technologies to effect this temporal control exist for
 
  • Dimming (both PWM and non-PWM)
  • Flicker control
  • Daylightng
  • Bio-centric color control
  • Real-time changes in lighting distributions: samples were shown at LightFair, contributing to QuarkStar winning the Lux Award for Top 10 Products at LightFair​
IOT Controls [top of page]

QuarkStar has developed pioneering IoT controls based on the OpenThread standard for both full scale building implementation as well as individual fixtures. Although previously unimplemented in the mainstream lighting industry OpenThread offers tremendous advantages over legacy networking protocols like Bluetooth and Zigbee.

QuarkStar's robust, self-healing mesh network system is based on the OpenThread Standard, a high-performance protocol originally developed by Google/Nest, and now supported by Apple, Amazon, Qualcomm, TI, Samsung – OpenThread is built on IEEE 802.15.4 (6LowPAN). The advantages of an OpenThread network are many:

  • OpenThread offers lower latency, better security, and enhanced resiliency compared to Bluetooth and Zigbee, using a fraction of the power required for WiFi.
 
  • OpenThread's routing is much superior to earlier protocols as well, being that each of our lighting nodes performs full routing (not flood-routing like others).
 
  • Using IPv6 addressability (providing 34 trillion trillion unique node addresses) allows for seamless integration with all current and future Internet applications.
 
  • A QuarkStar OpenThread Border Router in each lighting network provides extensive API capability, as well as physical implementation of Ethernet, DALI-2 and legacy 0-10 lighting controls interfaces.
 
  • QuarkStar lighting network control, commissioning, and maintenance can be performed locally via Bluetooth, Smartphones, and DALI-2, in addition to optional remote access via a secure Internet API.

Altogether, QuarkStar's IOT (Internet of OpenThread) system offers a unique early mover advantage to early adopters.
Control of Color [top of page]
 
QuarkStar is making fundamental breakthroughs in color shift prediction and stabilization. For example, being able to predict color shift curves using just existing LM-80 data, QuarkStar offers solutions to control and compensate for these shifts without complicated and costly feedback systems. This means simple, elegant solutions guaranteeing color behavior for end customers, competitive advantages to chip and package manufacturers, and significant impacts on the high-profile high-value downstream market.

QuarkStar Color Control Technologies include:

  • Long-term Color Shift Prediction of LEDs:   This is a solution to a previously unsolved problem and represents a newly developed ability to predict color shift in packages, modules, and luminaires. Elements of this brand new technological approach are already contributing to a new set of official industry standards (TM-35). See below for more on this topic.
 
  • Color Stabilization without active feedback: A patented long-term approach to stabilize multi-component LED color systems without the need for active feedback control loops. QuarkStar's team members are using the above referenced fundamental breakthroughs in color shift prediction to realize long-term color stabilization. By being able to predict color shift curves using just existing LM-80 data, this newly patented approach offers solutions to control that can compensate for these shifts without complicated and potentially costly active feedback systems.

This is a universal approach to passive color stabilization and appropriate for system use with any type of optics. This means simple, elegant solutions guaranteeing color behavior for end customers, competitive advantages to chip and package manufacturers, and significant impacts on the high-profile high-value downstream market.

 
  • Color Stabilization with active feedback:  Real-time control that takes advantage of the fact that colors from any solid-state sources are fully mixed within an Edge-X waveguide. This can be done in as small a waveguide height as a few tens of mm.
 
  • Color Rendition: At the package level, QuarkStar has several new ways to improve color rendition and chromaticity requirements without a negative impact on system efficacy.





Please contact QuarkStar directly if you are interested in broader in-depth discussions.

However, one of the developments, the ability to predict the long-term color shift of LEDs is already being used as part of the basis for the new IES Standard TM-35 on projecting long-term chromaticity shifts from LM-80 data. Some of the background and context is below, including links to presentations by its inventor – Dr. Eric Bretschneider.



Color Shift Prediction ​[top of page]


" ... a light source that shifts in color too much over time is just as useless as one whose lumen output drops below an acceptable threshold."

"SSL’s capability for excellent color stability has already been demonstrated, so as the technology continues to develop, there should be no need to compromise in that area for other performance attributes."
James Brodrick
Lighting Program Manager (retired), US Department of Energy
LD+A Magazine: Color Stability is Still a Question

Focus Shifts From Lumens to Color

"... [QuarkStar's model] has the potential to change how the solid-state lighting (SSL) industry utilizes test and measurement guidance, and effectively end the notion that the lumen is the only light characteristic that matters with regard to LED lifetime performance."

Carrie Meadows
LEDs Magazine: Focus Shifts From Lumens to Color
Picture
An example of how color can shift
in four different LEDs over time

The Problem

Color prediction - or, how to predict LED color shift behavior - and how to control it is a completely unsolved problem in LED lighting. It is considered one of the toughest problems in the field with no solution in sight ... until now.

The Solution

QuarkStar's CTO Dr Eric Bretschneider has developed a completely new solution that can accurately predict LED color performance over long time intervals using just existing LM-80 data and our DCA algorithms. This means that control systems to compensate for color shift and provide color stability can be created without complicated feedback systems.

Being able to offer these solutions will provide new opportunities to guarantee color behavior to customers and competitive advantages to chip and package manufacturers, significantly impacting the high-profile and high-value downstream market.

This ability to model and predict color stability behavior is already being incorporated into international industry standards.
Picture
Predictions of color shifting LEDs using
QuarkStar's DCA algorithms with LM-80 data

QuarkStar Presentations on Color Prediction Solutions

2019 Strategies in Light

Chasing the Rainbow - Developing a Single Predictive Model for LED Metrics
Watch Wecast
Presentation Slides

Presented by:
Dr. Eric Bretschneider
CTO QuarkStar
Chair of the IES Solid-State Lighting Subcommittee

Predicting chromaticity shift in LEDs and SSL products
(originally aired November 27, 2018)
​
Article based on Webcast: Focus Shifts from Lumens to Color

Lumen depreciation has been thoroughly studied in the solid-state lighting (SSL) world as the industry has sought to accurately predict the expected long lifetimes of LED-based products. But is a lighting product that significantly shifts in color or chromaticity over time still a viable product? Arguably, chromaticity shift can signal end of life just as easily as lumen depreciation in some applications.

Industry experts have been investigating ways to quantify chromaticity shift for enhanced LED performance testing. This webcast will provide an overview of how the SSL design process can be enhanced by predicting chromaticity shift. Product developers and lighting specifiers will learn how such a data-driven method might be employed to help them choose products carefully and to confidently deploy SSL technology in color-critical applications.

Presented by:
Dr. Eric Bretschneider
CTO QuarkStar
Chair of the IES Solid-State Lighting Subcommittee
Models for Color Point Stability of LEDs:
(originally presented at 2017 Strategies in Light)

Download presentation

According to conventional wisdom the issue of projecting the color point stability of LED packages requires detailed knowledge of the construction materials and package architecture. This information along with extensive testing would allow development of an accurate model for predicting color point stability for the specific package from given manufacturer. Any change of the materials whether it be phosphors, encapsulants or packaging materials would require additional testing and a new model.

Development of an industry standard method for projecting color point stability requires a model with minimal to no variables based on materials or supplier. As a result there is no currently accepted method for projecting color point stability.

Recently a model called Differential Chromaticity has been developed to address these needs. The model was developed by evaluation of LED test sets that extend from 12,000 - 20,000 hours and includes multiple types of packages from multiple suppliers. To date the model has proven robust and is able to model multiple color shift mechanisms without adjustable parameters. Different types of color shift mechanisms will be discussed along with the principles of Differential Chromaticity. Utility of the model in predicting different color shift mechanisms will also be discussed.

Presented by:
Dr. Eric Bretschneider
CTO QuarkStar