Spectrally selective tiling systems and methods for inducing or reducing non-visual responses to light

Abstract

A spectrally selective tiling system for inducing or reducing non-visual responses to light, including direct alerting responses and resetting of a human circadian clock, comprising at least one partition having alternatingly angled surfaces including (a) angled surfaces having a blue-enriched color, each configured to face a first direction and to reflect light incident from the first direction, and (b) angled surfaces having a blue-depleted color, each configured to face a second direction distinct from the first direction and to reflect light incident from the second direction.

Description

[0001] SPECTRALLY SELECTIVE TILING SYSTEMS AND METHODS FOR INDUCING OR REDUCING NON-VISUAL RESPONSES TO LIGHT

[0002] BACKGROUND

[0003] The discussion of the background state of the art below may reflect hindsight gained from the disclosed invention(s), and these characterizations are not necessarily admitted to be prior art.

[0004] Color, light, and their interaction within the built environment have always been pertinent spatial and aesthetic factors that architects consider in their work; however, their study has been limited to a primarily perceptual perspective. From antiquity to the Renaissance to Modernity and today, color, light, and their interaction within the built environment have always been key aesthetic and spatial factors that architects consider in their work.

[0005] On the other hand, light is the dominant environmental factor synchronizing the internal circadian pacemaker of most living organisms (including humans) and their entrainment to the 24-hour day. In 2000, the discovery of melanopsin and its role within the intrinsically photosensitive retinal ganglion cells (ipRGC) system in the human retina showed that the effect of light in this process is primarily non-visual. Thanks to the discovery of that system, we know that we humans need light not only for seeing but also for a series of biological functions related to our internal circadian rhythm, for example, alertness, sleep-wake cycles, cognitive performance, hormonal function, and thermoregulation. Additionally, clinical studies and scientific reports have shown that exposure to the wrong lighting conditions at the wrong time and, therefore, the disruption of the circadian rhythm can have a series of feedback effects, such as metabolic disorders, diabetes, and even some types of cancer. If we think of architecture as the spatial medium through which humans are exposed to light and its effects, the study of the biological effects of light on human health from both a physical and a cognitive perspective becomes of imperative importance for everyone in the related professions. Though the circadian rhythm and all its associated bodily functions are important topics, the following sections focus on daytime alertness and nighttime sleep as crucial light-related effects that have been associated with work, learning capability, and performance in schools, healing outcomes in hospitals, and improvement of physical and mental health in patients with dementia.

[0006] SUMMARY

[0007] Spectrally selective tiling system for inducing or reducing non-visual responses to light including direct alerting responses and resetting of a human circadian clock and methods therefor are described herein, where various embodiments of the systems and methods may include some or all of the elements, features, and steps described below. We herein study the relationship between color, light, and design from a physiological perspective, and, in particular, through the lens of newly discovered findings in human neuroscience and photobiology. Those findings pertain to the discovery of light as a promoter of alertness (or sleep) depending on its spectrum, as introduced through the discovery of a non-visual, photosensitive system in the human retina. That system consists of a network of intrinsically photosensitive retinal ganglion cells (ipRGCs) and is responsible for synchronizing human circadian rhythms and a series of associated bodily functions such as sleep / wake cycles and hormone production. The key photopigment that activates that system is melanopsin, a blue-light sensitive photopigment that, depending on the spectra and the illuminance of the light, triggers a biochemical cascade that signals the brain on the synchronization of the body’s daily rhythms. Specifically, melanopsin photoreceptors have a peak light absorption at light wavelengths of approximately 480 nanometers.

[0008] To date, research in lighting and photobiology has examined alertness and sleep effects mainly in relation to light spectra, overlooking the role of architectural surfaces and materials in the shaping of an environment's photobiological behavior. Moreover, research has not yet addressed photobiological behavior in an adaptive context where interiors are designed to affect both daytime- and nighttime-appropriate spectral content. To address this problem, we propose photobiological material systems as a design framework for spectrally selective surfaces that, in combination with adaptive lighting infrastructures, can promote alertness effects during the day and sleeppromoting effects during nighttime. The proposed framework is developed through a series of physical and simulation studies of increasing complexity, as well as a contextualization of the studies' results within contemporary theories of color and areas of architectural discourse.

[0009] Introduction of this new framework contributes to the areas of architectural design, lighting design, and photobiology in various aspects: at a fundamental level, the thesis produces new knowledge on how spatial elements, such as color, light, and surface geometry, contribute to an interior environment’s alertness and sleep effects on its occupants; from a standards perspective, it explores the limits of photobiological efficiency of commercially available color swatches when combined with light sources of different spectra; at an application level, the thesis introduces a new, science-grounded, and biology-driven framework for using color in design and architecture.

[0010] BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIGS. 1-3 illustrate a partition with static angled surfaces.

[0012] FIGS. 4-5 illustrate a partition with dynamic (rotatable) angled surfaces mounted in a static frame. FIG. 6 shows the position of internally photosensitive retinal ganglion cells (ipRGCs) on the human retina. Whereas rods and cones receive light inputs that are used for human color vision, ipRGCs are responsible for functions associated with nonvisual responses to light, including the effects of alertness and sleep.

[0013] FIG. 7 plots the wavelengths associated with the melanopic and photopic content of light. A higher M / P ratio leads to increased alertness and its associated biological functions, while a lower ratio promotes the opposite.

[0014] FIG. 8 includes plots of spectral power distribution (SPD) curves of LED sources of different correlated color temperatures (CCT).

[0015] FIG. 9 illustrates the spatial setup of Study I, described infra; and variables were consistent in the physical and the simulation environment.

[0016] FIG. io includes photographic images of six out of 18 physical environments tested with regards to their photobiological performance: (i) blue walls with a blue- enriched light source on the ceiling, (ii) red walls with a blue-enriched light source on the ceiling, (hi) white walls with a blue-enriched light source on the ceiling, (iv) blue walls with a blue-depleted light source on the floor, (v) red walls with a blue-depleted light source on the floor, (vi) white walls with a blue-depleted light source on the floor. For demonstration purposes, the sixth wall of the environment is removed.

[0017] FIG. n plots M / P values measured in the physical environment using the red- colored wall finish and under different combinations of light temperature (2700 Kfor the three sets of bars to the left and 500 Kfor the three sets of bars to the right), light source location, and measuring positions.

[0018] FIG. 12 plots M / P values measured in the physical environment using the whitecolored wall finish and under the different combinations of light temperature (2700 K for the three sets of bars to the left and 500 K for the three sets of bars to the right), light source location, and measuring positions, as in FIG. 11.

[0019] FIG. 13 plots M / P values measured in the physical environment using the bluecolored wall finish and under the different combinations of light temperature (2700 K for the three sets of bars to the left and 500 K for the three sets of bars to the right), light source location, and measuring positions, as in FIGS. 11 and 12.

[0020] FIG. 14 plots M / P values measured in the physical model (horizontal axis) using the ALFA software tool (vertical axis) and the red surface finish.

[0021] FIG. 15 plots M / P values measured in the physical model (horizontal axis) using the ALFA software tool (vertical axis) and the white surface finish.

[0022] FIG. 16 plots M / P values measured in the physical model (horizontal axis) using the ALFA software (vertical axis) and the blue surface finish.

[0023] FIG. 17 plots measured M / P values versus simulated M / P values for a red wall (at left), a white wall (center), and a blue wall (right). FIG. 18 illustrates the variables used to generate undulations on the spectrally selective wall surface, including (i) undulation size, (ii) side angularity, and (hi) curvature.

[0024] FIG. 19 shows the generated undulation profiles based on different undulation sizes, side angularity, and curvature values.

[0025] FIG. 20 shows generated wall designs were raytraced under two spatial setups, referred to as the following conditions: (a) the daytime condition, where the light source was positioned on the ceiling of the environment, and where measurements were taken at the 75% of the environment’s height, and (b) the nighttime condition, where the light source was positioned on the floor of the environment, and where measurements were taken at the 25% of the environment’s height.

[0026] FIG. 21 plots melanopic over photopic (M / P) values measured for the different undulation patterns of a blue-enriched surface under the daytime condition spatial setting with an undulated surface and a blue-enriched light source.

[0027] FIG. 22 plots melanopic over photopic (M / P) values measured for the different undulation patterns of a blue-depleted surface under the nighttime condition spatial setting with an undulated surface and a 2700-K light temperature.

[0028] FIG. 23 plots daytime-to-nighttime melanopic over photopic (M / P) values for different undulation angularities.

[0029] FIG. 24 shows selected blue-enriched and blue-depleted swatches, ordered on a photobiological scale (1-7) based on the degree to which they are blue-enriched or blue- depleted and also ordered on a perceptual scale that ranges from green to blue for the blue-enriched swatches and from red to brown for the blue-depleted swatches.

[0030] FIG. 25 shows the 49 two-colored, spectrally selective undulation profiles tested in Study III, discussed infra.

[0031] FIG. 26 illustrates the selection of swatches applied to upward- or down wardfacing sides of undulation components based on their spectrum (blue-enriched or blue- depleted). Combinations of color finishes on the undulated surface were measured under the daytime and nighttime conditions. In each condition, a light source of a blue- enriched or blue-depleted spectrum was placed either on the ceiling or on the floor of the environment, and spectrophotometric measurements were taken either from a higher or a lower horizontal plane.

[0032] FIG. 27 plots photobiological performance for the daytime condition as a result of the two-colored undulated wall.

[0033] FIG. 28 plots photobiological performance for the nighttime condition as a result of the two-colored undulated wall. FIG. 29 plots photobiological performance as a result of the two-colored undulated walls, with a focus on the difference, A, between the daytime and the nighttime M / P ratio.

[0034] In the accompanying drawings, like reference characters refer to the same or similar parts throughout the different views; and apostrophes are used to differentiate multiple instances of the same item or different embodiments of items sharing the same reference numeral. The drawings are not necessarily to scale; instead, an emphasis is placed upon illustrating particular principles in the exemplifications discussed below. For any drawings that include text (words, reference characters, and / or numbers), alternative versions of the drawings without the text are to be understood as being part of this disclosure; and formal replacement drawings without such text maybe substituted therefor.

[0035] DETAILED DESCRIPTION

[0036] The foregoing and other features and advantages of various aspects of the invention(s) will be apparent from the following more-particular description of various concepts and specific embodiments within the broader bounds of the invention(s). Various aspects of the subject matter introduced above and discussed in greater detail below may be implemented in any of numerous ways, as the subject matter is not limited to any particular manner of implementation. Examples of specific implementations and applications are provided primarily for illustrative purposes.

[0037] Unless otherwise herein defined, used, or characterized, terms that are used herein (including technical and scientific terms) are to be interpreted as having a meaning that is consistent with their accepted meaning in the context of the relevant art and are not to be interpreted in an idealized or overly formal sense unless expressly so defined herein. For example, if a particular composition is referenced, the composition may be substantially (though not perfectly) pure, as practical and imperfect realities may apply; e.g., the potential presence of at least trace impurities (e.g., at less than 1 or 2%) can be understood as being within the scope of the description. Likewise, if a particular shape is referenced, the shape is intended to include imperfect variations from ideal shapes, e.g., due to manufacturing tolerances. Percentages or concentrations expressed herein can be in terms of weight or volume. Processes, procedures, and phenomena described below can occur at ambient pressure (e.g., about 50-120 kPa— for example, about 90-110 kPa) and temperature e.g., -20 to 5O°C— for example, about 10- 35°C) unless otherwise specified.

[0038] Although the terms, first, second, third, etc., maybe used herein to describe various elements, these elements are not to be limited by these terms. These terms are simply used to distinguish one element from another. Thus, a first element, discussed below, could be termed a second element without departing from the teachings of the exemplary embodiments.

[0039] Spatially relative terms, such as “above,” “below,” “left,” “right,” “in front,” “behind,” and the like, maybe used herein for ease of description to describe the relationship of one element to another element, as illustrated in the figures. It will be understood that the spatially relative terms, as well as the illustrated configurations, are intended to encompass different orientations of the apparatus in use or operation in addition to the orientations described herein and depicted in the figures. For example, if the apparatus in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term, “above,” may encompass both an orientation of above and below. The apparatus maybe otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. The term, “about,” can mean within ±10% of the value recited. In addition, where a range of values is provided, each subrange and each individual value between the upper and lower ends of the range is contemplated and, therefore, disclosed.

[0040] Further still, in this disclosure, when an element is referred to as being “on,” “connected to,” “coupled to,” “in contact with,” etc., another element, it maybe directly on, connected to, coupled to, or in contact with the other element or intervening elements may be present unless otherwise specified.

[0041] The terminology used herein is for the purpose of describing particular embodiments and is not intended to limit more generic exemplifications of the invention. As used herein, singular forms, such as those introduced with the articles, “a” and “an,” are intended to include the plural forms as well, unless the context indicates otherwise. Additionally, the terms, “includes,” “including,” “comprises,” and “comprising” specify the presence of the stated elements or steps but do not preclude the presence or addition of one or more other elements or steps.

[0042] Additionally, the various components identified herein can be provided in an assembled and finished form; or some or all of the components can be packaged together and marketed as a kit with instructions (e.g., in written, video, or audio form) for assembly and / or modification by a customer to produce a finished product.

[0043] Introduction:

[0044] Spectrally selective tiling systems in the form of a partition 10 include blue- enriched surfaces 1 and blue-depleted surfaces 2 with different angled orientations. The positions and orientations of the blue-enriched surfaces 1 and blue-depleted surfaces 2 can be relatively fixed, as shown in FIGS. 1-3; or the positions and orientations of the blue-enriched and blue-depleted surfaces 1 and 2 can be adjustable via louvers 3 pivotably mounted to a fixed component 4, as shown in FIGS. 4 and 5. The light from these surfaces can enhance alertness (when light from the blue-enriched surfaces i reaches the human eye) or can promote sleepiness (when light from the blue-depleted surfaces 2 reaches the human eye).

[0045] The definition of blue-enriched and blue-depleted wall or surface colors is in accordance with the Munsell system, an established and widely accepted colorimetric framework for consistent and accurate color classification. Specifically, blue-enriched colors are defined (by the authors, and using the Munsell system) as hues predominantly within the Munsell system’s blue (B) to blue-green (BG) range, typically spanning from 5BG to 5BP. These colors exhibit a lightness value between 1 and 9 and a chroma (saturation) ranging from 2 to 14, creating a perceptible increase in blue dominance. Blue-depleted colors are defined as colors with hues predominantly outside the Munsell blue (B) to blue-green (BG) range, typically avoiding the spectrum from 5BG to 5BP. These colors have yellow (Y), orange (YR), or red (R) hues, with a lightness value between 1 and 9 and a chroma ranging from 2 to 14, creating a perceptible reduction in blue dominance.

[0046] Different materials can be characterized using the Munsell system as a helpful measure for quantifying their colors. The colors of surface materials (e.g., textiles, ceramics, paint, plastics, etc.), where color is quantifiable and stable, can be matched to color codes in the Munsell system. Though challenging, specific colorimetric measurements can even be used to match natural materials, such as wood or stone, to an existing color code. For highly reflective materials, such as glass or metals, the “natural” colors of these compositions can largely depend on incident light and surrounding reflections, so these factors can also be considered; and the undertones of a material may also need to be considered based on the lighting condition.

[0047] Non-Visual Response to Light and Alertness— Light as a Stimulant:

[0048] In mammals, light is perceived in the retina 5 of the eye after passing through the lens 6 not only by rods and cones 7, but also by a subset of intrinsically photosensitive retinal ganglion cells (ipRGCs) 8 (FIG. 6). Those cells critically contribute to nonimage-forming vision, a function affecting the regulation of sleep / wake cycles and in humans, also the control of several cognitive and behavioral functions, including mood and cognitive performance. This process is driven by the photopigment melanopsin.

[0049] In humans, melanopsin is maximally sensitive to photons in a distinct range of visible spectrum wavelengths, with a maximum wavelength of Xmax = 480 nanometers. Typically, light of wavelength close to Xmax is referred to, for brevity, as blue light or blue-enriched light, whereas light of higher spectral values is characterized as blue- depleted light.

[0050] For the human sleep-wake cycle, the science on the spectral sensitivity of melanopsin means that, when ipRGCs are exposed to light close to the max spectrum (or blue-enriched light), that light promotes alertness and wakefulness; when they are exposed to wavelengths above that level, such light promotes sleepiness by removing the alerting effects of light. A significant finding that emphasizes the separation of the visual and non-visual effects of light is that these effects have also been observed in individuals who are totally blind.

[0051] Through neural pathways from the eye to the brain, light activates non-visual brain areas related to alertness, sleep, and circadian rhythm. Exposure to light activates both melanopsin-containing ipRGCs, which are sensitive to short-wave wavelengths, and vision-responsible, classical ganglion cells (cRGCs), which are sensitive to midwavelength light. In turn, melanopsin-containing ipRGCs project to a range of ‘non- visual’ areas of the brain, including the suprachiasmatic nuclei (SCN), which then project multi-synaptically to the pineal gland, as well as to many areas that share input from the visual photoreceptor system, such as the lateral geniculate nucleus (LGN), pretectum and superior colliculus (SuC).

[0052] Through its activation of neurons at the SCN, which is the brain’s circadian pacemaker, and the release of pineal melatonin, light becomes a critical factor in the modulation of sleep and alertness.

[0053] The study of alertness effects and circadian behavior in relationship to spectral and lighting conditions has been an interdisciplinary and active field of study after the discovery of melanopsin. In the past two decades, numerous studies on the topic have been conducted, with spectral behavior examined mostly as a result of use-appropriate or varying spectrum (blue-enriched vs. blue-depleted). In this body of studies, experiment settings and user groups vary, with investigated groups being from healthy individuals to individuals with health conditions, such as dementia, and studies being conducted in environments that range from schools to workplaces to care homes.

[0054] A typical methodology followed by the examined body of studies is (a) the application of different lighting conditions (control and experimental) into a selected occupancy context, for example, a workplace setting or a school classroom; (b) exposure of the target group to the experimental conditions for an approximate of six hours for one or several days over the span of several weeks; and (c) assessment of the examined effect through self-reports, behavioral observations and / or tests. The significance of those methods is that they evaluate the non-visual effects of light based on spectral measurements in combination with physiological and / or qualitative data. In the context of the present thesis, this methodological aspect allows for adoption of spectral behavior components as predictors of circadian behavior. In particular, short wavelengths are associated with higher cognitive performance and learning capacity in school environments. A study conducted in a school setting and across students of similar performance reports an increase in concentration and cognitive processing speed in students who were exposed to blue-enriched classroom light (14,000 K) during the morning hours. Those results align with the results of previous studies that tested the same hypothesis about the efficacy of blue-enriched versus blue-depleted light on student cognitive performance through dynamic lighting applications where spectra and intensity were designed to fluctuate during the day based on the activity taking place.

[0055] Short wavelengths are also associated with higher levels of alertness and productivity in workplace environments. A study on 104 office workers demonstrated that blue-enriched white LED light (17,OOOK) significantly improved self-reported alertness, performance, and sleep quality in healthy individuals compared to white light (4,OOOK). In prior studies, working memory task performance has been associated with the wavelength of daytime light exposure.

[0056] Spectral behavior has recently been proven to have significant effects on environments of assisted living, especially regarding occupant alertness and injury prevention. In a recent multi-site study that included 189 care home residents and that was conducted over a span of 2 years, a 43% reduction in falls was reported as a result of the integration of blue-enriched lighting during the daytime. In a previous study, it was shown that blue-enriched, bright lighting conditions can reduce symptoms of depression and cognitive deterioration in elderly occupants of group care facilities.

[0057] Socially, culturally, and technologically, the discovery of this new science came at a time in which humans experienced an unprecedented exposure to the wrong light spectra and intensities at the wrong times, and for extended periods. Examples of that kind of exposure can come from various sources, for example, urban light pollution, the use of blue-light-emitting electronic devices during nighttime, exposure to office lighting beyond daytime, and even poor selection of indoor lighting, color, and material finishes. Numerous studies from the medical field demonstrate the cascading biological and health effects associated with light exposure and its impact on sleep / wake cycles and the circadian rhythm. Critical to the integration of this knowledge into contemporary indoor environments has been the acknowledgment of this science by international organizations and scientific committees, as well as the forming of guidelines for creating photobiologically safe, productive, and healthy spaces for working and living. The following section reviews the most recent standards, guidelines, and metrics that support this science and make it applicable to a design and architectural context.

[0058] Standards and Metrics for Evaluating Alertness Effects and Circadian Performance:

[0059] Translating the biological and health effects of wavelength spectrum into applicable knowledge and lighting guidelines has been made possible thanks to the work of international organizations and expert-driven scientific committees. The most up-to-date standards for quantifying the non-visual performance of light are the melanopic equivalent daylight illuminance (EDI) and the melanopic daylight efficacy ratio (m-DER) metrics, introduced by the International Commission on Illumination’s (CIE’s) S026-2018 System for Metrology of Optical Radiation for ipRGC-Influenced Responses to Light (CIE 2020). Those standards were based on metrics that had been previously developed to quantify ipRGC-dependent ocular light responses. Those previous metrics functioned as surrogate metrics due to their lack of objective measurement methodology. A review of the history of metrics developed after the discovery of the melanopsin system provides a thorough understanding of the components that shape an environment’s photobiological behavior and, additionally, justifies the selection of metrics used infra.

[0060] In 2013, an expert committee proposed a system weighing irradiance according to the effective spectral sensitivity of the five known human retinal opsin proteins, which are melanopsin, rhodopsin, S-, M-, and L-cone opsin. In this system, the melanopic (short-wavelength and non-image forming) content of light was measured in proportion to the amount of light received by long- and medium -wavelength sensitive rods and cones, referred to as the photopic content of light. This measurement has been referred to as the melanopic-over-photopic ratio (M / P), which, when at levels above 1.00, indicates an environment promoting wakefulness and alertness and, when at lower levels, indicates an environment promoting sleep. An example of how M / P represents circadian behavior through spectral properties is demonstrated in FIG. 7.

[0061] Before the introduction of the most recent CIE Toolbox and the m-DER metric, the M / P ratio served as a widely accepted, though constantly evolving and imperfect, metric for evaluating circadian behavior in international building standards, for example, the WELL V2-2019 building standard, as well as circadian lighting software, such as Solemma LLC’s Adaptive Lighting for Alertness (ALFA) software plugin for Rhinoceros 3D computer graphics and computer-aided design application software from Robert McNeel and Associates. The links of connection between the M / P ratio and commercial light sources and terminology are (a) the spectral power distribution (SPD) measurement of a luminaire, lamp, or daylight setting and (b) its translation into correlated color temperature (CCT), measured in degrees Kelvin (K). Whereas SPD represents spectral measurements, CCT represents a perceptual range of values where “warm” (long wavelength) white light is about 2700 K, “neutral” white light is about 4000 K, and “cool” (blue-enriched) white light is 5000 K or more (CIE 2020). FIG. 8 illustrates the relationship between wavelength, light source SPD, and the CCT of commercially available luminaires and lamps.

[0062] After several years of research, this framework has now been formalized into the equivalent daylight illuminance (EDI) and m-DER standards, which, based on spectral measurements, represent the biological effect of an artificial light source’s spectrum as referenced to daylight (CCT 6,5OOK). The metrology of the EDI and m-DER metrics is based on the measurement where the effective rates of photon capture for each of the human retinal opsins under a given light condition are equated to the photopic properties (e.g., illuminance) of a standard 6500 K (D65) daylight spectrum that would produce the same rate of photon capture. Brown, et al., “Recommendations for Daytime, Evening, and Nighttime Indoor Light Exposure to Best Support Physiology, Sleep, and Wakefulness in Healthy Adults.” PLoS Biology, Vol. 20, No. 3, Mar. 2022, p. 03001571, PubMed Central.

[0063] Whereas EDI is a metric representing illuminance levels compared to the D65 standard (measured in Lux), m-DER represents an efficacy ratio with regard to circadian performance (L.J.M. Schlangen and L.L.A. Price, “The Lighting Environment, Its Metrology, and Non-visual Responses,” 12 Front Neurol 624861, 2021), which makes it function as a more accepted standard than the M / P ratio. Naomi J. Miller and Anne C. Irvin, in “M / P Ratios— A Call for Consistency,” LD+A Magazine, Vol. 50, No. 2 (3 Feb. 2020), provide a comprehensive outline for the m-DER calculation based on the most recent CIE toolbox, with the major steps including (a) the measurement of a spectral measurement’s SPD values, (b) normalization of the value based on its melanopic weighting based on the D65 standard, (c) normalization of the value based on its photopic weighting based on D65, and (d) division of values.

[0064] This standardization allows for ease of adoption of the DER metrology system by designers, lighting professionals, organizations, and policymakers. Moreover, metricspecific recommendations by scientific committees have been developed to ensure the photobiological quality of indoor spaces throughout the day. During the daytime, the recommended minimum melanopic EDI is 250 lux at the eye measured in the vertical plane at approximately 1.2 m height; for evening time, the recommended maximum melanopic EDI at the same position is 10 lux, starting three hours before sleep. For nighttime, the recommended maximum ambient melanopic EDI is 1 lux measured at the eye level. Given the correlations between EDI, M / P, and / or DER and CCT, alertness and sleep-appropriate daylight and evening time recommendations can be followed through the use of blue-enriched and blue-depleted light, respectively. However, as shown by studies and introduced by experts, lighting alone is not enough to shape an environment’s appropriate photobiological performance, as other environmental factors that shape the spectral content of an interior environment can affect that process. A review of recent studies on how sleep / alertness effects can be affected by such factors, including material specifications and other spatial factors is developed in the next section. Alertness, Lighting, Architecture, and Materials: Findings, Tools, and Practices:

[0065] After the discovery of the non-visual effects of light on humans, studies in the areas of lighting engineering, building technology, and architecture have studied alertness effects and circadian behavior as a result of multiple factors that, in interaction with light, shape an environment’s spectral behavior. Such factors can include wall-color finishes, material furnishings, and, essentially, any spatial element that interacts with light, natural or artificial, and the way that it activates or suppresses melanopsin through ocular exposure. Considering that relationship, it maybe useful to think of architecture as the mediator between light and the parts of our brain that control our alertness, sleep, and the many cognitive, behavioral, and bodily functions that those states affect. In this new approach, viewer position, often referred to as field of view (FOV), becomes an important factor in the measurement of a space’s alertness effects or circadian performance. That dependency adds spatial, material, and casespecific aspects to what has previously been examined as a universally applicable set of guidelines.

[0066] In the past two decades, the development of software applications and studies in the context of the built environment have produced new knowledge and created new capabilities for predicting alertness effects through the design of the interior. A review of studies identifies several spatial factors that will be systematically studied infra to propose a new design framework that is based on the idea of adaptive spectral selectivity.

[0067] Light and Spatial Factors Affecting Spectra: Wall Properties as a Catalyst:

[0068] Spatial factors and wall material finishes have been studied as key elements affecting alertness and circadian behavior through their enhancement or diminishment of the spectral content of light produced by light sources. In these studies, properties of wall finishes, such as wall color and reflectance, have been proven to be the major factors affecting spectral behavior. A simulation study on healthcare architecture found that the circadian potential of an interior (that is, the environment’s spectral efficacy with regard to the human eye’s melanopic response) can be significantly affected by wall color, room orientation, and window-to-wall ratio. In the study, it was shown that, in rooms with identical window-to-wall ratios, walls painted in blue-deficient colors can degrade the created circadian stimulus. In a study in a residential house setting, it was found that, among several factors, including spatial layout, blind usage, and orientation, change in wall reflectivity alone (assuming a spectrally neutral finish) can create optimal circadian results, as it can lead to fewer losses of blue-enriched light coming from windows or other sources. Material finish color and optical properties in relation to alertness and circadian performance have also been studied, wherein it was demonstrated that textured finishes in combination with blue-enriched or neutral color finish can enhance the spectral composition of blue-enriched polychromatic light for certain points of view within a scene.

[0069] Studies such as the above contribute to a body of literature where alertness and circadian behavior are studied mainly as a result of lighting, assuming or using colorneutral material finishes. However, among other shortfalls, current research tends to assume environments where finishes are static, whereas lighting behavior is dynamic and, in the majority of cases, designed to enhance either daytime (alertness) or effects. To design not only for enhanced alertness but also for better sleep, we revisit the way that we design the spectral behavior of the interiors in a day-to-night scenario and think in terms of adaptive spectral selectivity (further described infra).

[0070] Software:

[0071] Taking into account the spatial aspects of alertness and circadian behavior, the development of software, such as ALFA (Adaptive Lighting for Alertness) software by Solemma LLC has enabled the simulation of spectral and, specifically, melanopic versus photopic (M / P) luminance metrics of a wide range of material finishes and integrated light sources using the technology of raytracing. ALFA software achieves accurate raytracing capacity using 81 color channels, which allows for more realistic simulation compared to previous, 3-channel raytracing software, such as RADIANCE software (from Lawrence Berkeley National Laboratory) for performing light simulation. Though not as advanced as ALFA software, RADIANCE software has been used by several studies to predict circadian behavior based on Red-Green-Blue channel luminance. More recent studies have estimated circadian values using multi-channel simulations.

[0072] This software and any other software referenced herein can be executed in a computing system environment, wherein the software can be non-transitorily stored in a computer-readable medium connected via a wired or wireless connection to a computer processor that can execute the instructions included in the software. In exemplary embodiments, the software can be stored and executed in a personal laptop or desktop computer or in a server or mainframe computer. Typical computing system environments and their operations and components are described in many existing patents (e.g., US Patent No. 7,191,467, owned by Microsoft Corp.).

[0073] Towards Adaptive Spectral Selectivity:

[0074] With studies proving the potential of color as an element with significant spectral-enhancing potential and having the tools to accurately simulate photobiological behavior, it is now possible to develop a systematic evaluation and understanding of color from a design-oriented, inclusive perspective. Moreover, in a contemporary context of advanced materials and fabrication methods, it is now possible to think of material finishes in terms of adaptive spectral selectivity in a day-to-night scenario that, for a variety of settings, such as work-from-home environments or healthcare facilities, increase blue-enriched light during the day and reduce it during nighttime. The following sections deploy a systematic exploration of that behavior and the new directions that it proposes for architecture, lighting, and design.

[0075] Current research in lighting and photobiology accordingly examines alertness / sleep effects and circadian behavior mainly in relation to light sources, with a few exceptions researching the additional contribution of architectural surfaces and materials. Even in the cases where material finishes are taken into consideration, prior research has not yet provided a systematic framework for designers to implement the related neuroscience into design using color finishes and other surface properties. Moreover, research has not yet addressed photobiological behavior from a daytime-to- nighttime use case scenario, assuming environments where material spectral behavior is static and lighting behavior is dynamic and thus designed to enhance either the desired daytime (alertness) or the nighttime (sleep) effects.

[0076] Based on this problem statement, the hypothesis that drives this investigation is that, while light sources of different spectra can improve an environment’s alertness / sleep-promoting effects, those effects maybe significantly limited by the spectral behavior of the material and other design components, such as color finish and surface geometry. In this phenomenon, “optimal” photobiological behavior is not tied to a strict range of wall surface properties but rather to ranges of properties, for example, ranges of blue-enriched or blue-depleted color finishes. Moreover, the design of spectrally selective surfaces that, in combination with an adaptive lighting infrastructure, can promote alertness effects during the day and sleep-promoting effects during the night is possible using a combination of the investigated properties in novel forms and design systems.

[0077] Described herein is a series of physical and simulation studies (briefly outlined below) of increasing complexity, as well as the development of design frameworks for implementing the studied science.

[0078] Study I - Spectra and Light:

[0079] This study serves as a baseline study evaluating the effect of the color finish of wall and floor material surfaces on the spectral behavior of a controlled environment. For the purpose of creating a scalable experimental setup for future studies, the study compares spectrophotometric measurements from the physical controlled environment with raytracing simulation measurements generated from its digital twin in order to establish fundamental knowledge as well as comprehension of the studied phenomenon’s simulation capacity. Study II - Spectra, Light, and Surface Geometry:

[0080] This study expands Study I, above, by investigating how aspects of wall-surface geometry, such as curvature and angularity in combination with color finish, further affect spectral behavior. This study is conducted in the simulated environment created for Study I.

[0081] Study III - Spectra, Light, and Surface Geometry: A Color-Inclusive Approach:

[0082] This study builds on the findings of Study II, above, to examine the limits of proper photobiological behavior using a range of color finishes in combination with surface geometry and light. This study concludes by ranking a broad range of color swatches based on their alertness vs. sleep effects, given a day-to-night, adaptive lighting scenario.

[0083] Relevance and Contributions:

[0084] This investigation contributes to the areas of architectural design, lighting design, and photobiology by proposing new approaches and systems for enhancing the alertness / sleep effects and, more broadly, the circadian behavior of the built environment. At a fundamental stage, this investigation produces new knowledge as to how spatial elements, such as color, light, and surface geometry, contribute to an interior environment’s alertness and sleep effects on its occupants. From a standards perspective, this investigation explores the limits of photobiological efficiency of commercially available color swatches when combined with light sources of different spectra. At an implementable stage, this investigation introduces a new, science- grounded, and biology-driven framework for using color in design and in architecture.

[0085] In this framework, spectrally selective surface systems are formulated to optimize an environment’s alertness and sleep effects when interacting with light. Where advanced materials in building settings may have the capacity to selectively adapt their physical properties, the photobiological behavior of the built environment maybe the result of both lighting and materials, a vision to which this investigation contributes with methods and proposed form vocabularies. At a discourse level, this investigation contributes to architectural literature with a new framework for analyzing and contextualizing the use of color in the architectural interior. This new framework updates long-standing (and often contradicting) perceptions of the psychophysical effects of color using a concrete and contemporary scientific background.

[0086] Study I - Spectra and Light:

[0087] Introduction:

[0088] This study serves as a baseline, with its two main goals being (a) to examine the effect of the combination of wall color finish and lighting conditions on alertness and circadian effect metrics and (b) to establish an understanding of the degree to which such effects can be simulated. The metric used to represent alertness effects is the ratio of melanopic-over-photopic luminance (M / P) within that environment, given a combination of spectral properties, lighting conditions, and other spatial factors. The study was developed using a combination of physical spectrophotometric measurements and raytracing using the ALFA software, which used M / P as an alertness and circadian performance metric at the time of the study. Whereas conversion from M / P to daylight efficacy ratio (DER) is possible, measurements used M / P as an original metric. In the evaluation of the observed data, and as described above, higher (>i.o) M / P ratios represent environments optimized for alertness, whereas lower (<0.40) ratios are indicative of environments promoting sleep. In the majority of use cases, higher M / P ratios would be advantageous in a daytime setting, whereas lower ratios would be the goal for nighttime settings. However, there maybe exceptions to that rule, such as in the case of shift work or other settings characterized by extreme time-shifting needs and conditions. This study explores edge cases in terms of the relationship between spectrum and surface color finish, that is, cases where three wall color finishes of high (alertness-promoting) or low (sleep-promoting) M / P measurements were tested either under blue-enriched (alertness-promoting) or blue-depleted (sleep-promoting) light sources.

[0089] The experiment used a combination of physical and simulation measurements to assess the environment’s impact on alertness effects. The physical measurements were collected using the COLORMUNKI portable spectrophotometer from X-Rite, Inc., in combination with the F.LUXOMETER software application from Flux Software, LLC. F.LUXOMETER software is a COLORMUNKI-compatible digital application for instant translation of spectrophotometric data into photopic and melanopic luminance measurements (F.LUXOMETER application, n.d.). The simulated measurements were produced using the RHINOCEROS environment with the GRASSHOPPER visual programming language and environment (from Robert McNeel & Associates) and the ALFA software plugin. To verify the accuracy of the simulation tool, each physical measurement was confirmed through a computational simulation.

[0090] The hypothesis driving Study I was that the color finish of interior surfaces, combined with changing lighting parameters, such as light temperature or location, has a significant impact on alertness and sleep effects. In a functional, real-world context, that hypothesis translates to a day-versus-night scenario where, in an interior environment, different combinations of wall color finish and lighting conditions, for example, a blue-enriched color finish combined with a higher-temperature lighting setting, would promote alertness during daytime; and a combination of a blue-depleted (red-looking) wall finish combined with a lower-temperature lighting setting would promote sleep during nighttime. Considering benchmarked M / P values for paint swatches and light sources, the tested combinations and their effects were expected; however, the significance of their combined effects had to be systematically studied, at the same time filling a gap in existing literature. At that early stage, it was also important to assess how other factors, such as measuring position or intensity of light, affect the measurements.

[0091] The experiment took place in a physical, controlled environment, and its digital simulation was performed using the McNeel RHINOCEROS 7.0 3D computer graphics and computer-aided design application using the ALFA software plugin. The main dependent variable was the M / P ratio, whereas the independent variables were (i) wall color, (ii) light temperature, (hi) light location and intensity, and (iv) measuring position. The values of all variables, and especially those of variables (i) and (ii), were selected taking into consideration the dual nature, physical and digital, of the experiment. In particular, both wall color and light temperature / spectrum were selected so that their respective values could be simulated using the ALFA software through its integrated material and lighting libraries.

[0092] Wall-color values were selected from ALFA software’s color swatch library so that they represent two edge cases and one neutral case of measured M / P values. Among the various swatch systems inside the ALFA software, values from the Munsell color system were selected. The purpose of that selection was the intention of accuracy between the physical and the simulation experiment environment, so that, in case simulation would be proven accurate within limits, it could replace physical measurements within the context of design exploration. Moreover, color values from the Munsell system can directly be translated into hex color values, which, in turn, can be matched to existing paint swatches using existing tools, such as the PROJECT COLOR app tool by the Home Depot Product Authority, LLC. As a blue-depleted wall color with a low M / P benchmarked value of 0.39, Munsell 5R 5 12 (#C7484E) was selected; as a color with a 1.00 M / P value, Munsell N9.5 (#F3F3EF) was selected, with an M / P value of 1; as a blue-enriched, higher-M / P color, Munsell 10B 6-10 (#2AAAD6) was selected, with an M / P value of 1.95.

[0093] Light sources and their types, intensity-wise and correlated color temperature (CCT)-wise, were selected so that they represent two edge cases of melanopic efficiency. Following the CIE standards of correlation between light-correlated color temperature (CCT) and melanopic efficiency, measured in M / P, a low-temperature (blue-depleted) source of 2700K CCT and a high-temperature (blue-enriched) source of 5000K CCT were selected. For consistency between the simulation model and the physical environment, LED, 6oW-equivalent, A-19 bulbs were selected as the form of the light source, with M / P values of 1.00 and 0.29 for the blue-enriched and the blue-depleted conditions, respectively.

[0094] Light-source location was selected in accordance with the daytime vs. nighttime scenario (described above), however, in a context where multiple lighting locations would be tested for benchmarking purposes. The initial assumption of this study was that artificial or natural light sources are located in positions above eye level (e.g., skylights, ceiling lights, or windows) in a daytime setting. During nighttime, light sources are placed in lower positions (e.g., table lamps, floor lights, or low-height wall lights). The combination of the specific wall-finish color and light temperatures had not been systematically tested in the existing literature. For the purpose of establishing benchmark metrics for future studies, three different lighting location setups were tested: one in which a light source of a specific temperature would be placed on the ceiling of the testing environment, one in which a light source of the same type would be placed on the floor of the tested environment, and one in which two light sources of the same type would be placed on the floor and the ceiling of the environment. Given the daytime vs nighttime scenario, in the case where alertness / sleep effects were measured using two light sources, those two sources were always of the same temperature.

[0095] The experiment and the related studies (discussed above) are highly dependent on the field of view (FOV) of occupants. In particular, studies take into consideration the spectral metrics of an environment’s lighting setting in relation to the occupant’s field of view, and, in particular, the measurement of light at the height of a human gaze, which translates to the height at which the human cornea is located. In literature, measuring height can vary based on the activities taking place in the studied environment. For example, in a study taking place in a school environment, metrics were taken at desk height, considering that students are sitting at a desk; in a study on care homes, measurements were taken at 136 cm, which is close to the eye level for seniors, many of whom use walking aids or are seated in a wheelchair, factors that affect their eye level. To gather data that would be useful in the design of FOV-dependent systems, spectrophotometric data were gathered from three different locations across the vertical axes, specifically, at 25%, 50%, and 75% of the environment’s height, height planes which translate to 95.25 mm, 190.50 mm, and 285.75mm> respectively.

[0096] The experiment’s independent variables and their values are illustrated in Table 1, below. Table i: Independent variables and values used in Study I:

[0097] Physical and Simulation Study Setup:

[0098] A schematic of the experiment’s spatial setup and variables is illustrated in FIG. 9. The environment included a cubical (381 mm x 381 mm x 381 mm) enclosure with six (6) internally removable thin walls. At the center of their surface, the floor and the ceiling of the box had a circular opening for the placing of the LED bulbs. Two E27 bulb sockets and their electrical supply cords were installed in two 50-mm-deep extensions of the box, placed above its ceiling and beneath its floor. As the illustration indicates, these two extensions had a utility purpose for the integration of the electrical devices and were entirely isolated from the main box apparatus. The front -facing side of the box had three 1.50-mm-wide, circular, removable covers. The openings were created for the purpose of measuring and were placed along the center axis of the wall’s width. From top to bottom, the first opening was located at 75% of the wall’s height (95.25 mm from the top), the second at 50% (190.50 mm from the top), and the third at the 25% (285.75 mm from the top). The size of the wall openings was designed to be narrow enough so that the sensor of the spectrophotometer would not be exposed to external light when attached to the measuring location, and wide enough to leave room around the sensor of the spectrometer.

[0099] As shown in FIG. 9, the (a) wall color was (i) red (Munsell 5R 5 12), (ii) white (Munsell N 95), or (hi) blue (Munsell 10B 6 10); the (b) light temperature was (i) 2700 K (blue-depleted light) or (ii) 5000 K (blue-enriched light); the (c) light-source location was (i) at the ceiling, (ii) between the floor and the ceiling, or (hi) at the floor; and (d) the light-measurement position was (i) at 0.75X the height of the room, (ii) at 0.50X the height of the room; or (hi) at 0.25X the height of the room.

[0100] FIG. 10 shows 6 out of the 18 physical environments (i-vi) tested (each environment was tested from three measuring positions), with walls of different wallcolor finishes being applied and under different lighting conditions. Environments (i) and (iv) are rooms with blue-enriched surfaces 1 of different shades, while environments (ii), (v), and (vi) are rooms with blue-depleted surfaces 2 of different shades [red in (ii) and (v) and orange in (vi)]. Environment (hi), meanwhile, is a room with white surfaces 9. Each environment (i)-(vi) includes light sources on the floor and ceiling. In environments (i)-(iii), the light source 10 at the ceiling level is activated, while, in environments (iv)-(vi), the light source 10 at the floor level is activated.

[0101] The simulation environment was designed to have the exact same form, dimensions, and properties as the physical environment. The software used to design the digital model was McNeel RHINOCEROS 7.0 software, and simulations were conducted using the ALFA software plugin. The environment included six 381 mm x 381 mm walls forming an enclosed box. For the assignment of color, assigning walls to a different layer in the RHINOCEROS software allowed the application of different colors using the ALFA software tool. For the light sources, two points in the RHINOCEROS environment were assigned as the reference points for the placement of bulbs using the ALFA software tool. The controls for temperature and visibility of light bulbs, so that the respective variables could be modified, were controlled under Luminaire Settings in the ALFA software tool. Three measurement locations were assigned using the Grids section in the ALFA software tool, where each measurement location was represented by one “View Plane” height. The measurement heights were located at 95.25 mm, 190.50 mm, and 285.75mmfrom the top of the box and across the vertical axis.

[0102] Study Process and Data Collection:

[0103] To measure the combined effect of wall finish and lighting on an environment’s alertness / sleep effects and its simulation capacity, 54 M / P and Lux measurements combining all examined wall colors, light temperatures, lighting source locations, and measuring positions were taken using the spectrophotometer. Additionally, 54 scenes of the environment were combinatorically modeled in the RHINOCEROS software environment and raytraced using the ALFA software tool. 216 data points were collected in total: 54 M / P measurements in the physical environment, 54 M / P measurements in the simulation model, 54 Lux measurements in the physical environment, and 54 Lux measurements in the simulation model. Whereas the primary assessment metric for alertness was the M / P ratio, the Lux level was important as a metric of photopic luminance for vision, especially during daytime.

[0104] Data and Results:

[0105] The data collected from the process described above are shown in Table 2, below. In addition to the M / P and Lux measurements for the measured environments, two columns were added to the table, each one presenting the difference between the respective measurements from the physical environment and the simulated environment. For each row, the numbers shown in the Delta column represent the value gathered from the physical measurement minus the value observed in the simulation experiment. Table 2 - Spectrophotometric data observed in the physical and the simulation environment for all combinations of variables and their values (Part 1): Table 2 - Spectrophotometric data observed in the physical and the simulation environment for all combinations of variables and their values (Part 2): Table 2 - Spectrophotometric data observed in the physical and the simulation environment for all combinations of variables and their values (Part 3): As the table demonstrates, in the physical experiment, M / P ratios in the red- colored environment ranged from 0.31 to 0.79, depending primarily on lighting temperature but also on the combination of light-source location and measurement height. M / Ps in the blue-colored environment were in a different, higher, and broader range that spanned from 0.62 to 1.69. Whereas in the case of the blue- and the red- colored environment, broad ranges of measurements were observed, M / Ps in the whitecolored environment had a stable value of either 0.48 when lit under a blue-depleted light source and 0.86 when lit under a blue-enriched source. In the simulation experiment, M / P ratios in the red-colored environment ranged from 0.27 to 0.89, depending primarily on lighting conditions, while M / Ps in the blue-colored environment were in a range that spanned from 0.6 to 1.82. M / Ps in the white-colored environment fluctuated between 0.44 and 1.04.

[0106] One of the preliminary results that derive from the collected data is that, both in the physical and the simulation experiment, wall color combined with lighting conditions has a significant effect on an environment’s alertness / sleep effects. That statement is to be further analyzed in the sections below regarding the study’s specific research questions and, in particular, those pertaining to the spatial factors contributing to the measured metrics and the simulation capacity of the studied phenomena.

[0107] Effect and Factors:

[0108] For the investigation of alertness and sleep effects, the measurements from the physical model were used. The simulation accuracy thresholds between the physical model and the simulation model are described in the next section. The results for each studied wall color finish are described below.

[0109] In the red-walled environment, the mean M / P under blue-depleted (2700 K) lighting was 0.37, as shown in the nine left-most plots, whereas the mean M / P for the blue-enriched (5000 K) lighting condition was 0.72, as shown in the nine right -most plots. As FIG. 11 demonstrates, the two lowest M / P values were 0.31 and 0.33, measured under the blue-depleted lighting condition in two spatially “symmetric” positions. Specifically, those values were observed either in the setup where, using a light source at the ceiling of the experimental environment, the measurement was taken close to the floor (at 25% of the environment’s height) or in the setup where, using a light source on the floor of the experimental environment, the measurement was taken close to the ceiling (at 75% of the environment’s height), and these three measurement positions are plotted from left-to-right for each light-source location (ceiling, ceiling and floor, and floor). In an environment isolated from outside noise, these two settings are technically the same, only flipped across the horizontal plane. In both cases, the result of the M / P ratio was affected by the distance between the light source and the measuring position. A similar pattern was observed for the two highest M / P values, which were 0.41 and 0.4 under the blue-depleted lighting condition and 0.77 and 0.79 for the blue-enriched condition; in all of these cases, as FIG. 11 shows, proximity between the light source and the measuring position led to a higher M / P ratio. The figure also shows that the number of light sources had a minor effect on the measured M / P metrics, increasing the ratio towards the median in all cases. FIGS. 12 and 13 include similar plots with the same light-source locations, light temperatures, and measuring positions for a white wall (FIG. 12) and a blue wall (FIG. 13).

[0110] The distance between the light source location and measuring position affected Lux levels. Table 2. shows that, under blue-depleted light, the scenes that had the lowest M / P ratios (0.31 and 0.33) as a result of the larger distance between the light source and measuring position were also the ones that had the lowest Lux levels (764.7 and 614.7, respectively). Under blue-enriched light, the scenes that had the lowest M / P ratios (0.6 and 0.65) were also the ones that had the lowest Lux levels (415.5 and 557.5, respectively). As the table indicates, Lux levels were also significantly affected by the number of light sources added to the environment. For example, the median luminance when two light sources were added to the environment, both in the blue-depleted and in the blue-enriched condition, was more than double what it was when only one source was placed either at the ceiling or on the floor of the environment (where median luminance = 2513 Lux for the blue-depleted condition and i860 Lux for the blue- enriched condition versus 988.9 Lux and 910.9, Lux respectively).

[0111] In the white-colored environment, a stable M / P of 0.48 was observed in the blue-depleted lighting condition; and an M / P fluctuating between 0.85 and 0.86 was observed in the blue-enriched lighting condition. Whereas in the red wall setting, the distance between the light source and measurement position affected the M / P ratio, no such effect was observed in the case of the white wall.

[0112] The most significant change in results from the white-wall experiment was that of luminance levels. Under the blue-depleted lighting condition, the mean luminance level was 4921 Lux; and, under the blue-enriched condition, the mean was 4276 Lux. Comparably to the Lux levels in the red-wall setting, the distance between measurement height and light-source position significantly affected the luminance levels, as Table 2 shows.

[0113] In the blue-colored environment, the mean M / P under blue-depleted lighting was 0.70, whereas the mean M / P for the blue-enriched condition was 1.4, which is, as in the case of the red wall, twice the mean observed under the blue-depleted lighting condition. Whereas, in the red-wall setting, a larger distance between the light source and measurement position resulted in lower M / P ratios, the opposite happened in the blue-wall setting. The two highest M / P values were 1.69 and 1.66, measured under the blue-enriched condition, in the spatially “symmetric” way that was observed in the red- colored wall. Specifically, the 1.69 value was observed in the setup where, using a light source on the floor of the experimental environment, the measurement was taken close to the ceiling (at 75% of the environment’s height). The 1.66 value was observed in a setup where, using a light source on the ceiling of the experimental environment, the measurement was taken close to the floor (at 25% of the environment’s height). The two lowest M / P values were 0.62 and 0.66 under the blue-depleted lighting condition and 1.27 and 1.29 for the blue-enriched condition. The number of light sources had a minor effect on the measured M / P metrics, increasing the ratio towards the median in all cases, as FIG. 14 shows, wherein FIG. 14 includes clusters of plots for light with temperatures of 2700 K 11 and 5000 K 12.

[0114] The distance between the light-source location and the measuring position affected Lux levels in the way that was observed in the red-colored environment: under blue-depleted lighting, the scenes that had the highest M / P ratios (0.77 and 0.78) were also the ones that had the lowest Lux levels (995.8 and 962.6, respectively). Under blue- enriched light, the scenes that had the highest M / P ratios (1.66 and 1.69) were also the ones that had the lowest Lux levels (628.4 and 613, respectively). As Table 2 demonstrates, another factor that significantly affected Lux levels was the number of light sources added to the environment. The median luminance when two light sources were added to the environment under both tested light temperatures was significantly higher compared to what it was when only one source was placed either at the ceiling or on the floor of the environment (where median luminance = 2456 Lux for the blue- depleted condition and 1783 Lux for the blue-enriched condition versus 1589 Lux and 978 Lux, respectively).

[0115] Simulation Accuracy and Capacity:

[0116] The physical experiment was replicated in a simulated environment that used the ALFA software plug-in. The purpose of this process was to examine the capacity to which the selected simulation tool can accurately predict alertness and sleep effects in an environment of identical color finish and lighting conditions, and, given that capacity, to assess the simulation potential of future studies. FIGS. 14-17 illustrate the relationship between measured M / P values in the physical environment (x-axis) and in the ALFA software plug-in (y-axis). The relationship between the values in the physical and the simulation environment was described using the linear regression formula, y = b*x + a, where y represents the M / P measurement in the ALFA software plug-in; x is the M / P measurement in the physical model; b is the slope of the regression line; and a is the y-intercept, which is the value of y when x equals zero. The additional statistical measurement, R2, was used as an indicator of how close to the regression line the generated data points are. Specifically, R2represents the coefficient of determination between simulated and physical data points, with R2values being closer to i, indicating a closer adjacency of points to the regression line.

[0117] The regression lines for the red (left), white (center), and blue (right) wall color finishes are shown in FIGS. 14, 15, and 16, respectively. FIG. 17 shows the correspondence between physical measurements and simulation measurements for all three color finishes for light temperatures of 2,yooK and 5,000 K. The line y = x is illustrated in all graphs for comparison to the case where the physical measurements would perfectly match with the simulation experiments. Specifically, for the red wall finish (at left), the linear equation of the regression line was y = i-43*x - 0.214, with the maximum delta between M / P values being equal to 0.18, the minimum delta being 0.01, and the mean equal to -0.01. For the white wall (center), the equation was y = 1.36* - 0.142, with the maximum delta between M / P values being -0.18, the minimum delta being equal to -0.02, and the mean being -0.08. For the blue wall (at right), the equation was y = i.o8*x - 0.05, with the maximum delta being -0.23, the minimum delta being -0.06, and the mean delta being -0.08. As the regression equations and the graphs indicate, a very strong correlation between physical and simulated measurements exists in the blue-colored finish, where b (1.08) is close to 1 and a (0.05) is close to zero, whereas weaker correlations exist in the case of the white and the red color finish.

[0118] In a practical scenario where a combination of color finish and lighting conditions would be designed to promote alertness and productivity, the regression line for the blue wall means that simulation is effective in predicting alertness and sleep effects. For the weaker correlations, especially for the red wall that is associated with the lowest M / P values (as demonstrated herein), the regression equation suggests that ALFA software calculations, especially under the blue-enriched lighting condition, produce higher values than physical measurements. In general, lowering an M / P value dynamically in a space is always feasible by lowering the level of luminance, whereas increasing an M / P value is not always possible as it highly depends on wavelength spectrum. Consequently, being able to accurately predict higher M / P values is, from an alertness / sleep effects perspective, more valuable than being able to predict lower values.

[0119] Whereas the analysis of the regression lines provides an understanding of correlations between physical and simulated values, R2provides input on the linearity of the relationship. Specifically, for the red-wall finish, the value of R2was 0.954; for the white-wall finish, R2was 0.974;and for the blue-wall finish, R2was 0.945. Those measurements suggest a high level of linearity in the examined relationships, which, in the context of the study variables, means that the combination of different color finishes with varying lighting, spatial, and measurement conditions affect an environment’s M / P ratio, and that finding is derived both from the physical and the simulation experiment.

[0120] FIGS. 14-16 illustrate the relationship between physical and simulated measurements in the three selected color finishes. Despite the variation of the regression-line slope between the three color finishes, the results of the simulation study align with the findings presented in the Effect and Factors section; in both environments, lower (< 0.5) M / P values are observed when blue-depleted lighting is combined with a red-hued finish, whereas higher (>1.4) M / P values are observed when blue-enriched is combined with a blue-hued finish. In the case of the neutral -hued finish, M / P values ranged from <=0.5 and up to 1, resulting in poorer alertness / sleep behavior both for daytime and nighttime conditions.

[0121] Discussion:

[0122] Study I (Spectra and Light) had the role of a baseline study where fundamental concepts, such as spectral behavior and alertness effects, were explored in quantitative terms in relation to surface color, lighting temperature, light source position, and measurement positions. Through the parallel development of a physical experiment and a simulated experiment, the study produced a series of findings related to the effect of such factors as well as the extent to which that effect can be simulated computationally.

[0123] The most significant finding of the study was that surface-color finish in combination with blue-enriched or blue-depleted lighting can significantly affect an environment’s alertness effects, with red wall hues in combination with blue-depleted lighting resulting in nighttime-appropriate M / P ratios, and blue wall hues in combination with blue-enriched lighting resulting in daytime-appropriate M / P ratios. In that dynamic, measuring position in combination with the position of the light source can have significant effects, especially in cases where a higher M / P is the goal. Moreover, assuming a uniform spectrum in all light sources of an environment, while the number of light sources significantly affects luminance levels, it does not affect M / P ratios, meaning that spectrum is the top determining factor in an interior’s alertness effects.

[0124] Regarding the ability of the observed behavior to be accurately simulated, Study I demonstrated that an environment’s alertness and sleep effects can be simulated at high levels of accuracy and within limits using existing software, such as the ALFA software plug-in. Whereas the ALFA software plug-in produced consistently higher M / P measurements in most combinations between variables, it proved to be particularly accurate in predicting higher M / P values. In a realistic context where the goal is to create photobiological conditions of alertness and wakefulness through higher M / P ratios, this ability is especially useful. Moreover, the linearity of the comparison model in the “Simulation Accuracy and Capacity” section, above, aligns with the linearity of results in the “Effect and Factors” section, above, where alteration of lighting and spatial conditions has a linear effect of M / P values (FIGS. 11-13).

[0125] Study II - Spectra, Light, and Surface Geometry:

[0126] Introduction:

[0127] Building on the findings of Study I, Study II (Spectra, Light and Surface Geometry) explored how wall-color finish in combination with surface geometry can optimize alertness and sleep effects. After the evaluation of the accuracy of the ALFA software calculations compared to a realistic setting, which was completed in Study I, Study II was developed entirely using simulations performed using the ALFA software. As in Study I, the metric for alertness was the ratio of melanopic-over-photopic luminance (M / P), with higher (>1.0) M / P ratios representing environments optimized for alertness and lower (<0.35) ratios being indicative of environments promoting sleep.

[0128] Existing research has shown that wall color, texture, and, in some cases, wallsurface finish reflectance alone can passively alter the spectrum of light received by the non-visual photoreceptor system. In the cited studies, a static material finish combined with dynamic lighting behavior can lead to spectrally selective surfaces. Despite the importance of surface selectivity as a photobiological concept, it is evident that studying surface selectivity using a uniform (blue-depleted or blue-enriched) surface finish can be limiting. That is because, given the setup of past studies, evaluation of alertness / sleep effects and / or circadian behavior refers to either a desired daytime or nighttime effect given a uniform finish. In many spatial settings where different activities take place throughout the day, for example, work-from-home settings, shift work locations, healthcare environments, or care homes, this framework can be limiting as it optimizes for (usually) blue-enriched daytime conditions, overlooking the need for a maximally blue-depleted setting during nighttime. This argument is supported by the findings of Study I, where, using a blue-enriched surface finish with a blue-enriched light source led to optimal daytime effects (mean M / P = 1.40), and using a blue- depleted surface finish in combination with a blue-depleted light source led to optimal nighttime effects (mean M / P = 0.37), whereas it was shown that using the same blue- enriched surface finish with a blue-depleted light led to significantly less optimal nighttime effects (mean M / P = 0.72).

[0129] Using the data of Study I as a reference and aiming to expand on existing findings on photobiologically effective spectral selectivity, Study II examined aspects of surface geometry as a potentially significant modifier of spectrum. Essentially, the study aimed to identify ways in which, given a static wall surface and a dynamic lighting setting, both alertness and sleep effects can be maximized for daytime and nighttime, respectively.

[0130] Using an environment with the same dimensions as in Study I, a simulation study was developed where spectrophotometric data were observed as a result of different surface geometry aspects in combination with color finish and lighting setup. The study was based on a daytime-to-nighttime spatial scenario where, given a dynamic lighting setup and a static, geometrical use of color finish, an environment can be high in melanopic content during daytime and low in melanopic content during nighttime. The form in which geometrical use of color finish was applied was a horizontally undulated surface with sloped sides, of which the upper side is of a blue-enriched color finish, and the lower side is of a blue-depleted color finish. This specific design setup was selected considering angle dependency as a condition allowing structural coloration of geometric surfaces. In the spatial context of an interior designed for the enhancement of occupant alertness / sleep effects, the dependency of spectral behavior on the angle of view means that points of view and areas exposed to a blue-enriched spectrum may have different photobiological effects from those exposed to a blue- depleted spectrum.

[0131] For consistency and evaluation purposes, we used color finishes that were identical to those used in Study I (Munsell 10B 6-10, M / P = 1.95 for the blue-enriched sides, and Munsell 5R 5 12, M / P = 0.39 for the blue-depleted sides). In the main study, the ceiling and the floor of the environment were white (Munsell N9.5, M / P: 1.00). The main dependent variable of the study was the M / P ratio, whereas the independent variables were geometrical element size, angle, and curvature.

[0132] The size of the geometrical element (undulation— i.e., including adjacent blue- enriched and blue-depleted surfaces) had the values of 1.8 mm, 3.6 mm, and 5.4 mm. The undulation sides had a complementary angular relationship, designed in increments of 15 degrees. The tested values were:

[0133] • 150upper side (blue-enriched finish) / 750lower side (blue-depleted finish),

[0134] • 30° upper side (blue-enriched finish) / 6o° lower side (blue-depleted finish),

[0135] • 450upper side (blue-enriched finish) / 450lower side (blue-depleted finish),

[0136] • 6o° upper side (blue-enriched finish) / 30° lower side (blue-depleted finish), and

[0137] • 750upper side (blue-enriched finish) / 150lower side (blue-depleted finish).

[0138] The undulation side curvature had the value of (i) none and (ii) curved, with a convex profile for the upper slope and a concave profile for the lower slope. The selection of the convex and the concave profiles was made with the assumption that profiles would function as lenses converging blue-enriched light rays or diverging blue-depleted rays to the measured focal points. The study variables and their values are illustrated in FIG. 18. The undulation elements, as generated using the variables and their values, at left with the dimensions (1.8 mm, 3.6 mm, and 5.4 mm) along their longest axes, are further illustrated in FIG. 19. Alternate flat 13 and curved 14 (convex upper side and concave lower side) surfaces of the undulation elements are also shown in FIG. 18.

[0139] The above variables and their combinations were applied and tested under the following two conditions: the daytime (blue-enriched) condition and the nighttime (blue-depleted) condition. A spatial setup was applied to each of the conditions, according to a realistic scenario where, during the day, blue-enriched light is needed in the height planes that are associated with work planes, walking, and / or meeting spaces, whereas, during nighttime, blue-depleted light sourced from a lower plane is sufficient for activities associated with sleep. Given that scenario, each of those conditions was specified as an angle-dependent combination of light-source spectrum, location, and measurement position.

[0140] In the daytime condition (lower left of FIG. 20), a blue-enriched light source (M / P: 1.00) was placed on the ceiling of the environment to direct blue-enriched light 15 down onto the blue-enriched surfaces 1 of the undulated surface 17. The light source was identical to that used in Study I. Spectrophotometric data were measured at 75% of the environment’s height, which translates to 95.25 mm from the height of the ceiling’s plane across the vertical axis.

[0141] In the nighttime condition (lower right of FIG. 20), a blue-depleted light source (M / P: 0.29) was placed on the floor of the environment to direct blue-depleted light 16 up onto the blue-depleted surfaces 2 of the undulated surface 17. The light source was identical to that used in Study I. Spectrophotometric data were measured at 25% of the environment’s height, which translates to 95.25 mm from the height of the floor’s plane across the vertical axis.

[0142] Pre-Study Evaluation:

[0143] The extent to which the ALFA software plug-in can accurately simulate spectrophotometric measurements given a flat wall of blue-enriched or blue-depleted finish was assessed in Study I. To adapt this assessment to the variables of Study II, a pilot experiment was performed prior to the main study both in a physical setting and using the ALFA software plug-in. In the experiment, physical spectrophotometric measurements were taken in the environment of Study I and compared with simulated measurements created using the ALFA software plug-in. Instead of four walls, the experiment used one undulated wall where the undulation size was 5.4mm, whereas the angularity was 450for the blue-enriched, upward-facing side and 450for the blue- depleted, downward-facing side. The undulation sides were flat, whereas the color finishes that were used were identical to the ones defined in the preceding section. From the physical and simulation results, it is evident that the simulation results are close to the physical results in the case of the single undulated wall. Because no major data dissonance was observed at this pilot stage, the main study was developed.

[0144] Study Process and Data Collection:

[0145] To measure the combined effect of wall-surface geometry and lighting given the two examined scenarios, 30 scenes were combinatorically modeled in the RHINOCEROS environment and raytraced using the ALFA software plug-in. 120 data points were collected in total: 30 M / P measurements for the daytime condition, 30 M / P measurements for the nighttime condition, as well as the respective Lux measurements for both conditions.

[0146] Data and Results:

[0147] The goal of the study was to explore the degree to which, given a specific lighting setup, the examined surface properties can enhance photobiological performance for both daytime and nighttime standards. Whereas Study I identified combinations between wall-color finish and lighting settings that maximize an environment’s photobiological performance either for alertness or for sleep, Study II explored whether, in a single environment, photobiological performance can be optimized both for daytime alertness and nighttime sleep. Given that objective, the criteria for evaluating the study results were not only how high or low the M / P was for the daytime or nighttime condition, respectively, but also the amplitude between the daytime and nighttime M / P.

[0148] The data collected from the process described above are shown in Table 3, below. In addition to the M / P and Lux measurements for the measured environments, the Delta column lists the amplitude between daytime and nighttime photobiological performance. The following two sections analyze the observed data as a result of the wall surface variables for the daytime-versus nighttime scenario, respectively, whereas the following section (Spectrally Selective Surfaces for Optimizing Day-to-Night Photobiological Performance) answers the question of how photobiological performance for both conditions can be optimized using a single, static, spectrally selective surface. Table 3: Spectrophotometric data measured using ALFA software for all combinations of variables and their values: Daytime Condition - Alertness Effects and Factors:

[0149] The objective of the nighttime condition is to explore the degree to which an undulated, two-colored surface’s geometrical properties can promote alertness under specific lighting conditions (blue-enriched, placed on the ceiling) and FOV location (75% of the environment’s height) through a high M / P ratio. The measurements observed for the daytime condition and under different combinations of undulation size, angularity, and curvature are illustrated in FIG. 21. From the diagram, it is evident that a blue-enriched side angularity of above 45 degrees contributed to a higher M / P ratio, whereas undulation size (1.8 mm, 3.6 mm, and 5.4 mm plotted left-to-right for each side angle) and curvature had a very small effect. In particular, the M / P means for angularities of 450, 6o°, and 750, respectively, had values of 1.17, 1.28, and 1.33 (FIG. 23), which are within the recommended range and significantly above the 1.03 value for Study I’s flat white-wall environment 18 when lit and measured under the same conditions (see Table 2). Moreover, the M / P ratios using those angularities, especially the 6o° and 750ones, were close to the M / P ratio of Study I’s flat blue-wall environment 19 (1-38).

[0150] The results observed for the undulated surface in the daytime condition demonstrate that an undulated wall with blue-enriched, upwards-facing sides and blue- depleted, downward-facing sides can have a photobiological performance that is significantly higher compared to that of a flat white wall and comparably efficient to that of a flat wall with a blue-enriched finish. In that relationship, angularity plays a significant role, whereas undulation size and curvature have minimal to no effect. The following section examines the same relationship with regard to the opposite photobiological effect.

[0151] Nighttime Condition: Sleep Effects and Factors

[0152] The objective of the nighttime condition was the opposite of the daytime condition, that is, to explore the degree to which the same surface-geometry properties can promote sleep (instead of alertness) under a different lighting condition (blue- depleted, placed on the floor) and field of view (FOV) location (25% of the environment’s height) through a low M / P ratio. The measurements observed for the nighttime condition and for different combinations of undulation size, angularity, and curvature are illustrated in FIG. 22. FIG. 22 illustrates that a blue-depleted side angularity of below 45 degrees (with the same undulation sizes and angles as are plotted in FIG. 21) contributes to a lower M / P ratio, whereas undulation size and curvature have minimal to no effect. In particular, the M / P means for angularities of 6o° and 750, respectively, had values of 0.36 and 0.32 (FIG. 23), which are within the recommended nighttime M / P range and significantly lower than the 0.50 value observed in Study I’s flat white-wall environment 18 when lit and measured under the same conditions (see Table 2). Moreover, the M / P ratios using those angularities were close to the M / P ratio of Study I’s flat red-wall environment 20 (0.28).

[0153] The results observed for the undulated surface in the nighttime condition demonstrate that an undulated, two-colored wall with blue-depleted, upwards-facing sides and blue-depleted, downward-facing sides, can have a nighttime photobiological performance that is significantly better compared to that of a flat white wall, and comparably efficient to that of a flat wall with a blue-depleted finish. In that relationship, angularity plays a significant role, whereas undulation size and curvature have minimal to no effect. Given the complementary arrangement of the angularities used in Study II (90°), it is evident that the value of the blue-depleted, downward-facing angle that contributes to a lower M / P ratio (75 °) in the nighttime condition is much higher than the 150blue-depleted angle that, in the daytime condition produces the highest M / P ratio through the 750, upward-facing, blue-enriched angle. Study I analyzes the data gathered in both examined conditions from a daytime-to-nighttime perspective where a single, two-colored, undulated surface can serve both conditions with the least possible compromises with regard to effect.

[0154] Spectrally Selective Surfaces for Optimizing Day-to-Night Photobiological Performance:

[0155] The preceding sections demonstrated that, through a complementary angular relationship, an undulated, two-colored wall surface with blue-depleted, upwards- facing sides and blue-depleted, downward-facing sides, can have varying photobiological performance under different lighting settings and measurement positions. Specifically, it is shown that the angle combinations that lead to optimal daytime photobiological performance contribute to an acceptable, yet not optimal, nighttime performance. From those combinations, all perform equally or, in most cases, better than the flat white wall both during daytime and nighttime, while only some perform as well as the flat blue and red wall, respectively. FIG. 23 illustrates the mean daytime M / P 21 (measured at 75% of the environment’s height using a blue-enriched light source), nighttime M / P 22 (measured at 25% of the environment’s height using a blue-depleted light source), and daytime-to-nighttime effect amplitude, A, for each angle combination, where that observation is shown in detail. For example, the 750blue-enriched side, facing upwards / 150blue-depleted side, facing downwards combination has the highest daytime performance (M / P=I.33), the largest amplitude of daytime-to-nighttime effect (A=o.97), but also the poorest nighttime photobiological performance (M / P = 0.55). On the other end of the results’ range, the 150blue-enriched side, facing upwards / 750blue-depleted side, facing downwards combination has the lowest daytime performance (M / P=o.97), the largest amplitude of daytime-to- nighttime effect ( =O.65), and the best nighttime photobiological performance (M / P = 0.32). To evaluate the observed results within the possibility of different ceiling and / or floor finishes, a post-study evaluation in which environments with walls of edge angularities (15 / 75 and 75 / 15) were raytraced with different combinations between floor and ceiling colors. Those colors were the blue-depleted finish of the study, the blue-enriched finish of the study, and gray (Munsell 5.5N, M / P 1.01). The results from those scenes have minimal to no difference from the results of the case in which the ceiling and the floor were painted white.

[0156] In a design context where, in a multi-use spatial setting that needs to be optimized both for daytime and nighttime photobiological performance, the selection of the daylight-promoting scenario would be most beneficial as daytime photobiological effects are the ones affecting work and cognitive performance, and additionally that sleep effects can be promoted by lowering lux levels or using a more blue-depleted color finish, a possibility that is further explored in Study III.

[0157] Discussion:

[0158] Study II (Spectra, Light, and Surface Geometry) is built on the results of Study I to explore how color finish, when applied in combination with wall geometry aspects, can produce alertness and sleep effects that are further enhanced than when applied on a flat, uniformly colored wall. Through the raytracing of a design space including 30 scenes, the study demonstrated that an undulated, two-colored wall surface with blue- depleted, upwards-facing sides and blue-depleted, downward-facing sides can have varying photobiological performance under different lighting settings and measurement locations. In that effect, it was shown that undulation side angularity is the number one factor affecting alertness / sleep effects, whereas undulation size and curvature have minimal to no effect.

[0159] Through its findings, the study contributes to relevant research both with fundamental knowledge and with new design approaches. With regards to existing literature and building on the contributions of Study I, the study provides photometric (versus previously used, less accurate, radiometric-based) evidence on how blue- enriched or blue-depleted finishes in combination with surface properties can significantly contribute to the alertness and sleep effects of a given interior. Moreover, it proposes how previously unexplored spatial attributes related to surface geometry can achieve photobiologically efficient spectral selection, both in a daytime setting where the blue content of received light needs to be increased and in a nighttime setting where it needs to be depleted. In a design reality where advanced fabrication processes allow the manufacturing of complex geometries and surfaces, the study generates knowledge that can be used in the design of buildings, spaces, and environments that promote healthy cycles of alertness and sleep for their occupants. The photobiological relevance of Study II encourages the further investigation of color as a spectrally altering factor in combination with geometry, however, from now on, from a design and architectural context. Whereas the explored color and geometry combinations led to significant results, the potential of those attributes to create palatable and aesthetic interiors remains unclear, given their bold, unusual hues and their combined visual effect. That very potential will be the topic of the next chapter, which will broaden the color palette used in Study II, examining how a broader yet curated and architecturally palatable spectrum can have comparable photobiological effects.

[0160] Study III - Spectra, Light, and Surface Geometry - A Color-Inclusive Approach:

[0161] Introduction:

[0162] This study researches the topic of Study II with an architectural and design- applicable context in mind. In Study II and through the spectrally selective, undulated wall system, it was shown that surface geometry aspects can significantly affect photobiological performance both in a daytime and a nighttime setting. However, the use of spectrally and visually specific hues may be limiting the application potential of that system and its adoption by architects and designers. To address that concern, Study III researches how blue-enriched and blue-depleted finishes belonging to a broader, more architecturally palatable color range can achieve desirable photobiological effects. Using the same undulated wall system as in Study II, the goal of the study is to examine how combinations between surface-geometry properties and color finish can have a photobiological performance comparable to that of the system explored in Study II. As in Study I and Study II, the metric for photobiological performance is the ratio of melanopic-over-photopic luminance (M / P), with higher (>0.9) M / P ratios representing environments optimized for alertness and lower (<0.35) ratios being indicative of environments promoting sleep.

[0163] Relevant literature examines color and paint finish properties as significant spectrally altering factors when applied uniformly on a wall surface. In Study II, it was discussed that the uniform application of color maybe photobiologically favoring either a daytime or a nighttime activity setting and how the use of spectrally selective, two- colored, undulated wall surfaces can address that. Building on those results, Study III will explore a broad range of possibilities of what those colors can be and what their photobiological potential is with regard to alertness / sleep effects. Building on the results of Study II, the study uses the angular relationship that was shown to be the most effective (750blue-enriched, upward-facing sides of a 750angle and blue-depleted, downward-facing sides of a 150angle) as a base to apply and test color. The smallest undulation size (1.8-mm height) was used for its contribution towards a more subtle two-colored visual effect.

[0164] The variables that were examined in Study II were the color finishes of the undulated surface sides in interaction with each other regarding their daytime and nighttime photobiological performance. Given that the study was developed using the ALFA software plug-in, color finishes were sourced from ALFA software’s swatch library, which, at the time of the study, included 209 color swatches of measured melanopic and photopic content and, therefore, photobiological performance. From this pool of colors, and within the objectives of the study, colors were selected so that (a) they represent a broad spectrum, appearance-wise, of both blue-enriched and blue- depleted swatches and (b) so that those swatches are also relatively evenly spaced within a range of appropriate M / P values, considering both the daytime (blue-enriched) and the nighttime (blue-depleted) lighting condition. Specifically, a range of seven blue- enriched swatches with M / P ratios ranging from 0.65 to 2.37 and a range of seven blue- depleted swatches with M / P ratios ranging from 0.26 to 0.59 were selected. The selected colors and their M / P values are represented in FIG. 24. For a more intuitive analysis purpose, the colors are ordered based on the degree to which they are blue- enriched or blue-depleted, i.e., the most blue-enriched swatch (M / P: 2.37) has an order of seven in the blue-enriched range, and the most blue-depleted swatch (M / P: 0.26) has an order of seven in the blue-depleted range. As FIG. 24 shows, the blue-enriched and blue-depleted swatches used in Studies I and II (Munsell 10B 6-10, M / P: 1.95 and Munsell 5R 5-10, M / P: 0.39) are included in the selected ranges for reference with regards to photobiological performance.

[0165] The colors and their combinations were tested on the undulated surface of 75° / 15° angularity, resulting in 49 different undulation unit profiles (FIG. 25). Spectrophotometric measurements were taken under Study Il’s daytime-to-nighttime scenario, where in the daytime condition (bottom left of FIG. 26), a blue-enriched light source (M / P: 1.00) was placed on the ceiling of the environment to direct blue-enriched light 15 down onto the blue-enriched surfaces 1 of the undulated surface. The light source was identical to that used in Studies I and II. Spectrophotometric data were measured at 75% of the environment’s height, which translates to 95.25 mm from the height of the ceiling’s plane across the vertical axis. In the nighttime condition (bottom right of FIG. 26), a blue-depleted light source (M / P: 0.29) was placed on the floor of the environment to direct blue-depleted light 16 up onto the blue-depleted surfaces 2 of the undulated surface. The light source was identical to that used in Studies I and II. Spectrophotometric data were measured at 25% of the environment’s height, which translates to 95.25 mm from the height of the floor’s plane across the vertical axis. Study Process and Data Collection:

[0166] The 49 generated scenes, each one using a uniquely colored undulation module, were raytraced in the ALFA software plug-in under the daytime and nighttime conditions.

[0167] Data and Results:

[0168] The goal of the study was to explore the degree to which, in a two-colored undulated surface and given a specific lighting setup, a range of combined color finishes can enhance photobiological performance for both daytime and nighttime standards. Whereas Study II identified surface-geometry properties that maximize an environment’s photobiological performance using one blue-enriched and one blue- depleted color finish on the surface undulations, Study III used color as its main variable. As in study II, the criteria for evaluating the study results were the resulted M / P levels both for the daytime and the nighttime condition as well as the amplitude (delta) between the daytime and nighttime M / P.

[0169] The data collected from the process described above are shown in Table 3, below. Additionally, to the M / P and Lux measurements for the measured environments, the Delta column lists the amplitude between daytime and nighttime photobiological performance. Similar to Study II, photobiological performance as a result of the two- colored, undulated wall was measured with regard to the M / P ratio for the daytime and nighttime conditions. The following sections analyze the observed data in terms of daytime, nighttime, and daytime-to-nighttime performance.

[0170] Table 3: Spectrophotometric data measured using ALFA software for all combinations of color swatches:

[0171] The colors of the swatches referenced in the above table are as follows:

[0172] • B-E 1 = Munsell Foliage Green (M / P: 0.67);

[0173] • B-E 2 = Dupont Green 47 (M / P: 0.80);

[0174] • B-E 3 = Munsell 5G 5-6 (M / P: 1.04);

[0175] • B-E 4 = Macbeth Bluish Green (M / P: 1.31);

[0176] • B-E 5 = Dupont Sky Blue 33 (M / P: 1.56);

[0177] • B-E 6 = Munsell 10B 6-10 (M / P: 1.95);

[0178] • B-E 7 = Dupont Dark Blue Grey 20 (M / P: 2.37);

[0179] • B-D 1 = Dupont Desaturated Yellow (M / P: 0.59);

[0180] • B-D 2 = Dupont Light Brown (M / P: 0.52);

[0181] • B-D 3 = Munsell 7.5 YR 5-6 (M / P: 0.46);

[0182] • B-D 4 = Munsell 5R 5-12 (M / P: 0.39);

[0183] • B-D 5 = Munsell 5YR 7-10 (M / P: 0.36);

[0184] • B-D 6 = Dupont Dark Yell 60 (M / P: 0.30); and

[0185] • B-D 7 = Macbeth Orange (M / P: 0.26).

[0186] Daytime Condition - Alertness Effects and Factors:

[0187] In the daytime condition, all swatch combinations applied on the undulated wall resulted in an M / P ratio of 0.99 and above. Regardless of the value of the blue-depleted swatch applied to the downward-facing sides of the undulations, the value of the blue- enriched swatch applied on the upward-facing sides of the undulations was proven to have a strong effect on the M / P ratio and its variations given a single blue-depleted swatch. For example, FIG. 28, which plots daytime condition M / P ratios 21 and nighttime condition M / P ratios 22 for different combinations of blue-depleted and blue-enriched color swatches, shows that, for all blue-depleted swatches, the cases in which they were combined with blue-enriched swatches 4 (bluish green-looking, Macbeth Bluish Green, M / P: 1.31), 5 (bright-blue-looking, Dupont Sky Blue 33, M / P: 1.56), and 6 (deep blue-looking, Munsell 10B 6-10, M / P: 1.95) resulted in M / P ratios that were significantly over 1.0 (> 1.15). When combined with blue-depleted swatches 1- 7, the mean M / P ratios resulting from walls that included blue-enriched swatches 4, 5, and 6 were 1.15, 1.20, and 1.30, respectively. Despite having a much higher base M / P ratio (2.37), blue-enriched swatch 7 resulted in lower M / P ratios than swatches 4, 5, and 6. Nighttime Condition - Sleep Effects and Factors:

[0188] In the nighttime condition, all swatch combinations applied on the undulated wall resulted in M / P ratios 22 ranging between 0.37 and 0.52. Independently of the value of the blue-enriched swatch applied to the upward-facing sides of the undulations, the value of the blue-depleted swatch applied on the downward-facing sides of the undulations was shown to have a moderate effect on the M / P ratio given a single blue- enriched swatch. In particular, FIG. 28 shows that, for all blue-enriched swatches, the cases in which a blue-enriched swatch was combined with blue-depleted swatches 1 (dusty yellow-looking, Dupont Desaturated Yellow, M / P: 1.59), 2 (neutral-looking, Dupont Light Brown, M / P: 0.52), 3 (brown-looking, Munsell 7.5YR 5-6, M / P: 0.46) and 7 (orange-looking, Macbeth Orange, M / P 0.26) resulted in M / P ratios 22 that were, in the vast majority of cases, below or equal to 0.4. Specifically, when combined with blue- enriched swatches 1-7, the mean M / P ratios 22 resulting from walls that included blue- depleted swatches 1, 2, 3, and 7 were 0.37, 0.37, 0.38, and 0.39, respectively. At first glance, that is a rather surprising finding considering that blue-depleted swatches 1-3 have base M / P ratios of 0.59, 0.52, and 0.46, respectively, whereas blue-depleted swatches 4-7 all have M / P ratios that are equal to, or below, 0.39. Given those metrics and for a uniformly colored flat wall, it would be expected that the lower nighttime M / P ratios would result from the swatches with the lower M / P base ratios, which are blue- depleted swatches 4-7 within the context of the study. A look into the data of the daytime scenario reveals that that finding is connected to the daytime M / P metrics. Thus, the use of a blue-enriched swatch of higher base M / P in combination with a blue- depleted swatch of a lower M / P hindered the effects of the blue-depleted swatches. The exception in that case is blue-enriched swatch 7, where its use in combination with all blue-depleted swatches resulted in M / P ratios that were below 0.40.

[0189] Building on the results of Study II, Study III demonstrated that, using a two- colored undulated wall, it is possible to achieve high M / P ratios in a daytime setting and lower M / P ratios in a nighttime setting using a broader range of swatches. However, within possible ranges, dynamics can be significantly affected by the combination of blue-enriched and blue-depleted swatches, the photobiological relationship between which is not always linear.

[0190] Daytime-to-Nighttime Photobiological Performance:

[0191] The analysis of the observed data from a daytime-to-nighttime perspective helps in identifying color combinations that, in an applicable context, maximize photobiological performance both during a daytime and a nighttime lighting and spatial context. As FIG. 29 shows, the 49 color combinations resulted in photobiological behavior that varied with regard to the Delta (A) between the daytime M / P ratio 21 and the nighttime M / P ratio 22 within each scene. Specifically, measured Deltas ranged between 0.61 and 0.83. For each blue- depleted swatch, the Delta was the lowest when the swatch was combined with blue- enriched swatch 1 and, in most cases, gradually increased for each blue-enriched swatch with a peak in blue-enriched swatch 6. The highest Deltas were observed in the cases where the blue-enriched swatch 6 (deep blue-looking, Munsell 10B 6-10, M / P: 1.95) was combined with blue-depleted swatches 1 (olive green-looking, Munsell Foliage Green, M / P: 0.67), 7 (orange-looking, Macbeth Orange, M / P 0.26), and 2 (neutral-looking, Dupont Light Brown, M / P: 0.52).

[0192] Comparing those results with the ones pertaining to daytime and nighttime photobiological performance, it is evident that there is a correlation between higher Deltas and higher M / P ratios during the daytime condition. However, those Deltas refer to cases in which the daytime M / P ratio is high, and the nighttime ratio is low but not optimally low. For example, the 0.83 (highest) Delta results from a 1.31 daytime M / P ratio, which is ideal, and a 0.48 nighttime ratio, which is appropriate but not the lowest M / P ratio observed.

[0193] Discussion:

[0194] Study III built on the results of Study II to explore how a broad range of blue- enriched or blue-depleted color finishes, when applied on a geometrical surface with spectrally selective undulations, can enhance the photobiological performance of an interior both in a daytime and in a nighttime setting. Through the raytracing of 49 scenes under two conditions each, the study demonstrated that an undulated, two- colored wall surface with upward-facing sides colored with a range of blue-enriched swatches and downward-facing sides colored with a range of blue-depleted swatches.

[0195] A significant finding of the study was that, in a two-colored, spectrally selective environment, the effects of blue-enriched swatches of higher base M / P ratios can be hindered when in combination with a blue-depleted swatch of a lower M / P, even when they occupy the majority of the wall surface through a dominant blue-enriched angularity (75 °). Thus, for such systems to be effective, attention must be drawn to the use of blue-depleted swatches. Those findings invite further discussion on the selection of swatches in the design of spaces that consider both a daytime, blue-enriched spectral environment and a blue-depleted one.

[0196] The study completes a three-part series of studies exploring color in combination with architectural attributes as critical factors in an interior’s photobiological performance, directing toward new ways of designing interior architectural surfaces and finishes. The use of a broad, architecturally curated, and palatable color palette is strategic and reflects an intention to propose a system that can be part of an enjoyable and aesthetically pleasing architectural space. Additional Exemplifications:

[0197] In additional exemplifications, the partition can be positioned in other orientations (rather than vertical)— e.g., on or in ceilings or floors and the light sources can be repositioned accordingly. The partition can also be non-fixed— e.g., in the form of a movable panel that can be placed on a desk or table or be in the form of a moveable partition. The partition can also be temporarily hung from the wall or ceiling or stood up on the floor of the room.

[0198] In contrast with partitions having static surfaces, as shown in FIGS. 1-3 (with blue-enriched surfaces 1 and blue-depleted surfaces 2), the angled surfaces of the partition can also be dynamic, as shown in FIGS. 4 and 5, in terms of being displaceable so as to be oriented at different angles during the day. For example, the angled surfaces can be different sides of louvers that can be mounted in a frame or hung from a mount above and suspended, e.g., with strings secured to front of back sides of the louvers, and the angles of the louvers can be changed by retracting the strings on one side of the louvers and releasing the strings on the other side of the louvers as is practiced with window blinds that include louvers. Alternatively, each louver can be mounted on a central shaft that can be rotated e.g., by a rotary motor connected thereto) to change the angles of the louvers. Via this actuation, the differently colored surfaces of the partition can each be positioned at their optimal angle with respect to the incident light when light exposure of that color is desired. The dynamic partition shown in FIGS. 4 and 5 includes blue-enriched surfaces 1 and blue-depleted surfaces 2 on louvers 3 rotatably connected to a fixed component 4.

[0199] The schedules via which the angled surfaces are exposed to the incident light can be aligned, e.g., with the path of the sun (including sunrise and sunset) at the site of the partition. In other applications, the partition can be used, e.g., in space (aboard a spacecraft) where the partition can be used to replicate natural lighting conditions matched to the path of the sun at a particular location on Earth so as to set the circadian rhythm of an astronaut at a fixed a familiar pattern.

[0200] In other applications, such as in a hospital or other medical facility, patients and medical workers (staff) maybe on different sleep schedules. For example, medical professionals working the night shift may benefit from exposure to blue-enriched light at night and into the early morning to enhance their alertness, while patients may benefit from sleep at times when the medical staff is active. Consequently, the partition can be designed, e.g., to reflect blue-depleted light at the height of a bed on which the patient is resting or attempting to sleep, while at the same time reflecting blue-enriched light at greater heights so as to be received by the eyes of medical workers who are standing upright or sitting (where their heads would still be higher than if they were lying on a bed). In additional exemplifications, more than two angled surfaces can be provided, which can include at least two angled surfaces / sections that reflect light at different wavelengths in the blue domain, such as at about 440 nm (e.g., at 430-450 nm) to stimulate visual photoreceptors in the human eye, e.g., during the first hour (or 2 or 3 hours) when the blue-enriched light can stimulate the photoreceptors to promote alertness to an enhanced degree before declining. Different surfaces (or sections of surfaces) can further be provided with a blue-enriched color at about 480 nm (e.g., at 470-490 nm) to stimulate melanopsin-containing intrinsically photosensitive retinal ganglion cells in the eye to promote alertness over a longer period of time, particularly after the effects of the initial stimulation of visual photoreceptors wears off. The different colors / shades can alternatively be provided, e.g., a cylindrical or multi-faceted roller that is rotated to expose different angled surfaces / sections to be exposed to the incident light.

[0201] In additional exemplifications, the shades of blue-enriched color can be shifted by changing the character e.g., via a chemical reaction) of the blue-enriched angled surface in a way that produces a shift in color. This result can be achieved by including any of the following in or on the blue-enhanced angled surface: a thermochromic composition that changes color as a function of temperature and provision of a heat and / or cooling source to change the temperature of the composition so as to generate the color change; an electrochromic composition that changes color with the application of electric current and provision of a voltage source to provide the electric current to the composition; and mechanophore molecules that change states in response to an external force, wherein those states reflect different color shades, and provision of an actuator to provide that external force to the composition when actuated. In additional exemplifications, the angled surfaces can include smart glass or switchable glazing or can include a liquid crystal display (LCD).

[0202] Operation of the light sources and positioning of the angled surfaces (in a dynamic system) can be automatically governed by a computer, wherein the computer includes a processor in communication with the various adjustable components of the system and computer-readable memory nontransitorily storing instructions for, e.g., activating the light sources and for repositioning the angled surfaces to receive incident light according to a desired schedule for alertness / sleepiness in a human whose eyes receive the light reflected by the angled surfaces. For example, the angled surfaces can be rotated to track the path of the sun across the sky (to receive the incident sunlight therefrom). In other exemplifications, displaceable mirrors or lenses can be used to redirect sunlight onto the angled surfaces.

[0203] As an alternative to using artificial light sources, the system and method can utilize light from the sun as the light incident upon the angled surfaces, particularly for the blue-enriched light that promotes alertness, which is typically provided during the daytime.

[0204] Though room-scale configurations have been described, the partition including the angled surfaces can be at the “furniture-scale,” such as, for example, providing the angled surfaces on a desk-level partition placed on a desk or on the floor adjacent to a desk such that the person sitting at the desk will be directly exposed to light reflected by the desk-level partition.

[0205] In describing embodiments herein, specific terminology is used for the sake of clarity. For the purpose of description, specific terms are intended to at least include technical and functional equivalents that operate in a similar manner to accomplish a similar result. Additionally, in some instances where a particular embodiment includes a plurality of system elements or method steps, those elements or steps may be replaced with a single element or step. Likewise, a single element or step maybe replaced with a plurality of elements or steps that serve the same purpose. Further, where parameters for various properties or other values are specified herein for embodiments, those parameters or values can be adjusted up or down by 1 / 100th, 1 / 50th, 1 / 20th, 1 / 10th, 1 / 5th, 173rd, 1 / 2, 2 / 3rd, 3 / 4* 4 / 5th, 9 / ioth, 19 / 20*, 49 / 50*, 99 / 100*, etc. (or up by a factor of 1, 2, 3, 4, 5, 6, 8, 10, 20, 50, 100, etc.), or by rounded-off approximations thereof or within a range of the specified parameter up to or down to any of the variations specified above (e.g., for a specified parameter of 100 and a variation of 1 / 100th, the value of the parameter maybe in a range from 0.99 to 1.01), unless otherwise specified. Further still, where methods are recited and where steps / stages are recited in a particular order— with or without sequenced prefacing characters added for ease of reference— the steps / stages are not to be interpreted as being temporally limited to the order in which they are recited unless otherwise specified or implied by the terms and phrasing.

[0206] Additional examples consistent with the present teachings are set out in the following numbered clauses:

[0207] 1. A spectrally selective tiling system for inducing or reducing non-visual responses to light, including direct alerting responses and resetting of a human circadian clock, the system comprising: at least one partition having alternatingly angled surfaces, including: angled surfaces having a blue-enriched color, each configured to face a first direction and to reflect light incident from the first direction; and angled surfaces having a blue-depleted color, each configured to face a second direction distinct from the first direction and to reflect light incident from the second direction.

[0208] 2. The spectrally selective tiling system of clause 1, wherein the partition is vertically oriented.

[0209] 3. The spectrally selective tiling system of clause 2, wherein the angled surfaces having the blue-depleted color face upwardly at a prescribed angle, and wherein the angled surfaces having the blue-enriched color face downwardly at a prescribed angle.

[0210] 4. The spectrally selective tiling system of clause 2, wherein the partition is a wall, and wherein the angled surfaces face an interior of a room.

[0211] 5. The spectrally selective tiling system of clause 4, wherein the room further comprises a ceiling and a floor, and wherein the wall has a top edge and a bottom edge, the system further comprising: a ceiling joined with the top edge of the wall and extending from the wall; a floor joined with the bottom edge of the wall and extending substantially orthogonally from the wall; a blue-enriched light source configured to generate light that is primarily in the blue-enriched spectrum of visible light, wherein the blue-enriched light source is either in an upper half or in a lower half of the room and is configured to direct blue-enriched light onto the angled surfaces having the blue-enriched color; and a blue-depleted light source configured to generate light that is primarily in the blue-depleted spectrum of visible light, wherein the blue-depleted light source is either in a lower half or in an upper half of the room, opposite the blue- enriched light source, and is configured to direct blue-depleted light onto the angled surfaces having the blue-depleted color.

[0212] 6. The spectrally selective tiling system of clause 5, wherein the blue-enriched light source is in the upper half of the room, and wherein the blue-depleted light source is in the lower half of the room.

[0213] 7. The spectrally selective tiling system of clause 1, further comprising: a blue-enriched light source configured to generate light that is primarily in the blue-enriched spectrum of visible light, wherein the blue-enriched light source is configured to direct blue-enriched light onto the angled surfaces having the blue-enriched color; and a blue-depleted light source configured to generate light that is primarily in the blue-depleted spectrum of visible light, wherein the blue-depleted light source is configured to direct blue-depleted light onto the angled surfaces having the blue-depleted color.

[0214] 8. The spectrally selective tiling system of clause 7, wherein the partition and the blue-enriched light source are configured to promote alertness in a human exposed to blue-enriched light reflected by the angled surfaces having the blue- enriched color.

[0215] 9. The spectrally selective tiling system of clause 7 or 8, wherein the partition and the blue-depleted light source are configured to promote sleepiness in a human exposed to blue-depleted light reflected by the angled surfaces having the blue- depleted color.

[0216] 10. The spectrally selective tiling system of any of clauses 7-9, wherein at least one of the light sources is an artificial light source.

[0217] 11. The spectrally selective tiling system of any of clauses 7-10, wherein at least one of the light sources is the sun.

[0218] 12. The spectrally selective tiling system of clause 1, wherein the angled surfaces are configured to dynamically change position as a function of time.

[0219] 13. The spectrally selective tiling system of clause 12, wherein the angled surfaces are configured to change their angle with a shift after dusk at the site of the panel.

[0220] 14. The spectrally selective tiling system of clause 12 or 13, where the configuration to change the position of the angled surfaces comprises an actuator mechanically coupled with the angled surfaces and configured to displace the angled surfaces when actuated.

[0221] 15. The spectrally selective tiling system of clause 14, wherein the angled surfaces are on a cylinder or a prismatic shape, and wherein the actuator is configured to rotate the cylinder or prismatic shape.

[0222] 16. The spectrally selective tiling system of any of clauses 1-15, wherein the angled surfaces having the blue-depleted color are less reflective than the angled surfaces having the blue-enriched color.

[0223] 17. The spectrally selective tiling system of any of clauses 1-16, wherein the angled surfaces are configured to change color shades.

[0224] 18. The spectrally selective tiling system of clause 17, wherein the angled surfaces comprise at least one of the following: a thermochromic composition that changes color as a function of temperature; an electrochromic composition that changes color with the application of electric current; or mechanophore molecules that change states in response to an external force, wherein those states reflect different color shades. - The spectrally selective tiling system of any of clauses 1-18, wherein the spectrally selective tiling system comprises at least three angled surfaces with different color shades. . The spectrally selective tiling system of clause 19, wherein the color shades include: a first blue-enriched color shade that reflects light at a wavelength in a range from 430 to 460 nm; a second blue-enriched color shade that reflects light at a wavelength in a range from 460 to 510 nm; and a blue-enriched color that reflects light at a wavelength in a range from 530-700 nm. . The spectrally selective tiling system of any of clauses 1-19, wherein the angled surfaces include a first angled surface with a blue-enriched color of a first color shade that reflects light at a wavelength in a range from 450 to 510 nm and a second angled surface with a blue-enriched color of a second color shade that reflects light at a wavelength in a range from 530 to 700 nm. . The spectrally selective tiling system of any of clauses 17-21, further comprising a computing device including a processor and computer-readable memory in communication with the processor, wherein the computer-readable memory non-transitorily stores software code for effecting a change in the blue-enriched color shades as a function of time when executed by the processor. . The spectrally selective tiling system of clause 22, wherein the software code stored in the computer-readable memory further includes instructions for changing the blue-enriched color shades exposed to incident light from a first color shade that reflects light at a wavelength in a range from 430 to 460 nm to a second color shade that reflects light at a wavelength in a range from 460 to 510 nm. . The spectrally selective tiling system of clause 23, wherein the instructions for changing the color shades are synchronized with a position of the sun relative to the Earth at the site of the partition. . The spectrally selective tiling system of any of clauses 1-24, wherein the angled surfaces comprise a smart or switchable glass that changes color via application of an electric current to the smart glass. . The spectrally selective tiling system of any of clauses 1-24, wherein the angled surfaces comprise a programmable liquid crystal display (LCD). . A method for enhancing alertness or promoting sleep using the spectrally selective tiling system of any of clauses 1-2 in a room, the method comprising: emitting light of a blue-depleted color; directing the light of the blue-depleted color onto the angled surfaces having the blue-depleted color; in the room, reflecting in the room the light of the blue-depleted color from the angled surfaces having the blue-depleted color; emitting light of a blue-enriched color; directing the light of the blue-enriched color onto the angled surfaces having the blue-enriched color; and in the room, reflecting the light of the blue-enriched color from the angled surfaces having the blue-enriched color.

[0225] 28. The method of clause 27, further comprising reflecting the light of the blue- enriched color from the angled surfaces having the blue-enriched color and reflecting the light of the blue-depleted color from the angled surfaces having the blue-depleted color to an eye of at least one human in the room.

[0226] 29. The method of clause 28, wherein the same human receives the light of the blue- enriched color and the light of the blue-depleted color but at different times.

[0227] 30. The method of clauses 28 or 29, wherein the human receives the light of the blue-enriched color during the daytime when the sun is above the horizon at the location of the partition and the human.

[0228] 31. The method of any of clauses 28-30, wherein the human receives the light of the blue-depleted color during the nighttime when the sun is below the horizon at the location of the partition and the human.

[0229] 32. The method of any of clauses 28-31, wherein receiving the light of the blue- depleted color enhances sleepiness of the human receiving the reflected light of the blue-depleted color, and wherein receiving the light of the blue-enriched color enhances alertness of the human receiving the reflected light of the blue- enriched color.

[0230] 33. The method of any of clauses 28 or 30-32, wherein a first human receives the reflected blue-depleted light at the same time that a second human receives the reflected blue-enriched light.

[0231] 34. The method of clause 33, wherein the room is in a medical facility, and wherein the first human is a medical patient, and wherein the second human is a medical worker.

[0232] 35. The method of any of clauses 27-34, wherein the light of the blue-enriched color is reflected upwardly, and wherein the light of the blue-depleted color is reflected downwardly.

[0233] 36. The method of any of clauses 27-35, wherein the light is emitted by at least one artificial light source. 37- The method of clause 36, wherein the light of the blue-depleted color is emitted downwardly from an artificial light source in an upper half of the room, and wherein the light of the blue-enriched color is emitted upwardly from an artificial light source in a lower half of the room.

[0234] 38. The method of any of clauses 27-37, wherein the light of the blue-depleted color is reflected from the angled surfaces having the blue-depleted color over a time period distinct from a time period over which the light of the blue-enriched color is reflected from the angled surfaces having the blue-enriched color.

[0235] 39. The method of any of clauses 27-38, further comprising changing the color shade of the blue-enriched color of the angled surface exposed to the blue-enriched light as a function of time.

[0236] 40. The method of clause 39, wherein the color shade is changed by changing the blue-enriched color of the angled surface via at least one of the following means: applying or removing heat from a thermochromic composition on or in the angled surfaces having the blue-enriched color, wherein the thermochromic composition changes color as a function of temperature; increasing or decreasing application of electric current to an electrochromic composition on or in the angled surfaces having the blue- enriched color, wherein the electrochromic composition changes color with the change in the application of electric current; or applying an external force to mechanophore molecules on or in the angled surface having the blue-enriched color, wherein the mechanophore molecules change states in response to the external force, and wherein those states reflect different color shades.

[0237] 41. The method of clause 39, wherein the angled surfaces having the blue-enriched color include sections having a blue-enriched color of a shorter wavelength and sections having a blue-enriched color of a relatively longer wavelength, the method further comprising the displacing the angled surfaces to reflect the light of the blue-enriched color first with the sections having the blue-enriched color of the shorter wavelength and then with the sections having the blue-enriched color of the longer wavelength.

[0238] 42. The method of any of clauses 39-41, further comprising receiving in an eye of at least one human in the room the light reflected from the angled surface sections having the blue-enriched colors of the shorter wavelengths, wherein light of the blue-enriched color of the shorter wavelength produces an enhanced effect on visual photoreceptors in the human eye to increase alertness in the human, and wherein light of the blue-enriched color of the shorter wavelength produces an enhanced effect on melanopsin-containing intrinsically photosensitive retinal ganglion cells in the human eye to increase alertness in the human.

[0239] While this invention has been shown and described with references to particular embodiments thereof, those skilled in the art will understand that various substitutions and alterations in form and details may be made therein without departing from the scope of the invention. Further still, other aspects, functions, and advantages are also within the scope of the invention; and all embodiments of the invention need not necessarily achieve all of the advantages or possess all of the characteristics described above. Additionally, steps, elements, and features discussed herein in connection with one embodiment can likewise be used in conjunction with other embodiments. The contents of references, including reference texts, journal articles, patents, patent applications, etc., cited throughout the text are hereby incorporated by reference in their entirety for all purposes; and all appropriate combinations of embodiments, features, characterizations, and methods from these references and the present disclosure may be included in embodiments of this invention. Still further, the components and steps identified in the Background section are integral to this disclosure and can be used in conjunction with or substituted for components and steps described elsewhere in the disclosure within the scope of the invention.

Claims

CLAIMSWhat is claimed is:

1. A spectrally selective tiling system for inducing or reducing non-visual responses to light, including direct alerting responses and resetting of a human circadian clock, the system comprising: at least one partition having alternatingly angled surfaces, including: angled surfaces having a blue-enriched color, each configured to face a first direction and to reflect light incident from the first direction; and angled surfaces having a blue-depleted color, each configured to face a second direction distinct from the first direction and to reflect light incident from the second direction.

2. The spectrally selective tiling system of claim 1, wherein the partition is vertically oriented.

3. The spectrally selective tiling system of claim 2, wherein the angled surfaces having the blue-depleted color face upwardly at a prescribed angle, and wherein the angled surfaces having the blue-enriched color face downwardly at a prescribed angle.

4. The spectrally selective tiling system of claim 2, wherein the partition is a wall, and wherein the angled surfaces face an interior of a room.

5. The spectrally selective tiling system of claim 4, wherein the room further comprises a ceiling and a floor, and wherein the wall has a top edge and a bottom edge, the system further comprising: a ceiling joined with the top edge of the wall and extending from the wall; a floor joined with the bottom edge of the wall and extending substantially orthogonally from the wall; a blue-enriched light source configured to generate light that is primarily in the blue-enriched spectrum of visible light, wherein the blue-enriched light source is either in an upper half or in a lower half of the room and is configured to direct blue-enriched light onto the angled surfaces having the blue-enriched color; and a blue-depleted light source configured to generate light that is primarily in the blue-depleted spectrum of visible light, wherein the blue-depleted light source is either in a lower half or in an upper half of the room, opposite the blue-enriched light source, and is configured to direct blue-depleted light onto the angled surfaces having the blue-depleted color.

6. The spectrally selective tiling system of claim 5, wherein the blue-enriched light source is in the upper half of the room, and wherein the blue-depleted light source is in the lower half of the room.

7. The spectrally selective tiling system of claim 1, further comprising: a blue-enriched light source configured to generate light that is primarily in the blue-enriched spectrum of visible light, wherein the blue-enriched light source is configured to direct blue-enriched light onto the angled surfaces having the blue-enriched color; and a blue-depleted light source configured to generate light that is primarily in the blue-depleted spectrum of visible light, wherein the blue-depleted light source is configured to direct blue-depleted light onto the angled surfaces having the blue-depleted color.

8. The spectrally selective tiling system of claim 7, wherein the partition and the blue-enriched light source are configured to promote alertness in a human exposed to blue-enriched light reflected by the angled surfaces having the blue- enriched color.

9. The spectrally selective tiling system of claim 7, wherein the partition and the blue-depleted light source are configured to promote sleepiness in a human exposed to blue-depleted light reflected by the angled surfaces having the blue- depleted color.

10. The spectrally selective tiling system of claim 7, wherein at least one of the light sources is an artificial light source.

11. The spectrally selective tiling system of claim 7, wherein at least one of the light sources is the sun.

12. The spectrally selective tiling system of claim 1, wherein the angled surfaces are configured to dynamically change position as a function of time.

13. The spectrally selective tiling system of claim 12, wherein the angled surfaces are configured to change their angle with a shift after dusk at the site of the partition.

14. The spectrally selective tiling system of claim 12, where the configuration to change the position of the angled surfaces comprises an actuator mechanicallycoupled with the angled surfaces and configured to displace the angled surfaces when actuated.

15. The spectrally selective tiling system of claim 14, wherein the angled surfaces are on a cylinder or a prismatic shape, and wherein the actuator is configured to rotate the cylinder or prismatic shape.

16. The spectrally selective tiling system of claim 1, wherein the angled surfaces having the blue-depleted color are less reflective than the angled surfaces having the blue-enriched color.

17. The spectrally selective tiling system of claim 1, wherein the angled surfaces are configured to change color shades.

18. The spectrally selective tiling system of claim 17, wherein the angled surfaces comprise at least one of the following: a thermochromic composition that changes color as a function of temperature; an electrochromic composition that changes color with an application of electric current; or mechanophore molecules that change states in response to an external force, wherein those states reflect different color shades.

19. The spectrally selective tiling system of claim 1, wherein the spectrally selective tiling system comprises at least three angled surfaces with different color shades.

20. The spectrally selective tiling system of claim 19, wherein the color shades include: a first blue-enriched color shade that reflects light at a wavelength in a range from 430 to 460 nm; a second blue-enriched color shade that reflects light at a wavelength in a range from 460 to 510 nm; and a blue-enriched color that reflects light at a wavelength in a range from 530-700 nm.

21. The spectrally selective tiling system of claim 1, wherein the angled surfaces include a first angled surface with a blue-enriched color of a first color shade that reflects light at a wavelength in a range from 450 to 510 nm and a second angled surface with a blue-enriched color of a second color shade that reflects light at a wavelength in a range from 530 to 700 nm.

22. The spectrally selective tiling system of claim 17, further comprising a computing device including a processor and computer-readable memory in communication with the processor, wherein the computer-readable memory non-transitorily stores software code for effecting a change in the blue-enriched color shades as a function of time when executed by the processor.

23. The spectrally selective tiling system of claim 22, wherein the software code stored in the computer-readable memory further includes instructions for changing the blue-enriched color shades from a first color shade that reflects light at a wavelength in a range from 430 to 460 nm to a second color shade that reflects light at a wavelength in a range from 460 to 510 nm.

24. The spectrally selective tiling system of claim 23, wherein the instructions for changing the color shades are synchronized with a position of the sun relative to the Earth at the site of the partition.

25. The spectrally selective tiling system of claim 1, wherein the angled surfaces comprise a smart or switchable glass that changes color via application of an electric current to the smart glass.

26. The spectrally selective tiling system of claim 1, wherein the angled surfaces comprise a programmable liquid crystal display (LCD).

27. A method for enhancing alertness or promoting sleep using the spectrally selective tiling system of claim 1 in a room, the method comprising: emitting light of a blue-depleted color; directing the light of the blue-depleted color onto the angled surfaces having the blue-depleted color; in the room, reflecting the light of the blue-depleted color from the angled surfaces having the blue-depleted color; emitting light of a blue-enriched color; directing the light of the blue-enriched color onto the angled surfaces having the blue-enriched color; and in the room, reflecting the light of the blue-enriched color from the angled surfaces having the blue-enriched color.

28. The method of claim 27, further comprising reflecting the light of the blue- enriched color from the angled surfaces having the blue-enriched color and reflecting the light of the blue-depleted color from the angled surfaces having the blue-depleted color to an eye of at least one human in the room.

29. The method of claim 28, wherein the same human receives the light of the blue- enriched color and the light of the blue-depleted color but at different times.

30. The method of claim 28, wherein the human receives the light of the blue- enriched color during the daytime when the sun is above the horizon at the location of the partition and the human.

31. The method of claim 28, wherein the human receives the light of the blue- depleted color during the nighttime when the sun is below the horizon at the location of the partition and the human.

32. The method of claim 28, wherein receiving the light of the blue-depleted color enhances sleepiness of the human receiving the reflected light of the blue- depleted color, and wherein receiving the light of the blue-enriched color enhances alertness of the human receiving the reflected light of the blue- enriched color.

33. The method of claim 28, wherein a first human receives the reflected blue- depleted light at the same time that a second human receives the reflected blue- enriched light.

34. The method of claim 33, wherein the room is in a medical facility, and wherein the first human is a medical patient, and wherein the second human is a medical worker.

35. The method of claim 27, wherein the light of the blue-enriched color is reflected upwardly, and wherein the light of the blue-depleted color is reflected downwardly.

36. The method of claim 27, wherein the light is emitted by at least one artificial light source.

37. The method of claim 36, wherein the light of the blue-depleted color is emitted downwardly from an artificial light source in an upper half of the room, and wherein the light of the blue-enriched color is emitted upwardly from an artificial light source in a lower half of the room.

38. The method of claim 27, wherein the light of the blue-depleted color is reflected from the angled surfaces having the blue-depleted color over a time period distinct from a time period over which the light of the blue-enriched color is reflected from the angled surfaces having the blue-enriched color.39- The method of claim 27, further comprising changing the color shade of the blue- enriched color of the angled surface exposed to the blue-enriched light as a function of time.

40. The method of claim 39, wherein the color shade is changed by changing the blue-enriched color of the angled surface via at least one of the following techniques: applying or removing heat from a thermochromic composition on or in the angled surfaces having the blue-enriched color, wherein the thermochromic composition changes color as a function of temperature; increasing or decreasing application of electric current to an electrochromic composition on or in the angled surfaces having the blue- enriched color, wherein the electrochromic composition changes color with the change in the application of electric current; or applying an external force to mechanophore molecules on or in the angled surface having the blue-enriched color, wherein the mechanophore molecules change states in response to the external force, and wherein those states reflect different color shades.

41. The method of claim 39, wherein the angled surfaces having the blue-enriched color include sections having a blue-enriched color of a shorter wavelength and sections having a blue-enriched color of a relatively longer wavelength, the method further comprising displacing the angled surfaces to reflect the light of the blue-enriched color first with the sections having the blue-enriched color of the shorter wavelength and then with the sections having the blue-enriched color of the longer wavelength.

42. The method of claim 41, further comprising receiving in an eye of at least one human in the room the light reflected from the angled surface sections having the blue-enriched colors of the shorter wavelengths, wherein light of the blue- enriched color of the shorter wavelength produces an enhanced effect on visual photoreceptors in the human eye to increase alertness in the human, and wherein light of the blue-enriched color of the shorter wavelength produces an enhanced effect on melanopsin-containing intrinsically photosensitive retinal ganglion cells in the human eye to increase alertness in the human.

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