Humans, animals, and plants have evolved under illumination from the sun filtered by the atmosphere. Daylight as we perceive it, is a continuous spectrum of wavelengths from 380 nm to 780 nm. From near UV to near IR the human eye detects light, the spectral content (color) and intensity of daylight as it changes throughout the day. Among other factors, light also changes based on latitude, season, and atmospheric phenomena like clouds or rain. Data from a recording of daylight during an afternoon on Mt. Hamilton in San Jose, CA can be seen on the right. Our experience and biological response are tuned to this time, intensity, and color varying light. The complete day cycle is called the circadian rhythm. This time dependent light rhythm has always been a part of our experience and vocabulary - dawn, noon, golden hour, dusk, blue hour, and twilight among the many. And that is why people want the window office - to experience and thrive by what the body has adapted to over a very long time.
Much of the time “daylight” chromaticity (color appearance) does not map to the daylight or blackbody locus we use to classify light sources. So far, no artificial light sources have come close to the rich spectrum and time varying characteristics of daylight.
Telelumen technology is based on hardware, firmware, and software. Telelumen takes the key ingredients of software, LED solid state light, high performance drivers, and portable spectrometers to create a light fixture that can produce custom spectral power distributions (SPDs) that can change over time and intensity. An intuitive and easily mastered user interface creates custom spectra using standard lighting parameters such as CCT, recorded spectra, and synthesized SPDs as inputs to produce the desired light output. Alternatively, a graphics equalizer type input can manipulate each color channel individually. From designing spectral power distributions to study circadian rhythms to studying plant growth, the possibilities to manipulate the light spectrum are endless.
Current products use 16 or 8 independent color channels of LED light to create the output. With 16 channels you get scientific instrument level capability and flexibility to easily design experiments where a live subject or sensors can be tested for reaction to precision light stimulus. With 8 channels you have a flexible commercial grade light fixture for living spaces or a research tool. In either case, the capability to record or create time varying light spectra to be “played” by the fixture give the user unparalleled control of the light. At all times the light output can be dimmed to very low levels over any time profile.
Why do people always want the office by the window?
The rationale for selecting more color channels is seen in the graph above. It plots the quality of the light (CQS in this case) against the correlated color temperature (CCT) range for systems using various “channel/color” configurations. The coverage and quality of the light output can be seen for 2 to 10 channel configurations. In general more colors translates into higher color quality over a broader range of color temperatures.
Recorded on Mt. Hamilton, San Jose, California, March 9, 2011