The lighting domain is changing from off-the-shelf point solutions towards 24/7 meaningful lighting services. This research program is contributing to this development through a program that demonstrates the value of light for human functioning with evidence-based research.

It has adopted an agenda of translational and integrative research: it seeks to perform the research that is necessary to test the relevance and implications of very fundamental insights for daytime exposure, day- active people, and in real-world applications, and is integrative in the sense that it builds on various scientific disciplines and includes both image-forming and non-image forming effects of light, in the service of pro- moting health, wellbeing and sustainability.

Its agenda pertains to a range of research lines of human functioning: (1) perception, (2) emotion, (3) cognition, (4) health and (5) interaction/user control, and a final, integrative line (6) Light and building design. It focuses on application domains of (a.) care, (b.) home, (c.) work and (d.) public spaces. Research includes experiments in controlled labs and living labs, simulation studies, and real-world field studies.

Within this research program we focus on these six interrelated challenges:

1. Perception – Seeing better and more comfortably
   In this research line, our ambition is to improve vision through lighting. First of all, fundamental research is performed to extend our knowledge on human visual perception. Secondly, we investigate how light characteristics (such as brightness, color, diffuseness and dynamics) influence the appearance of objects, spaces and light itself depending on the application and the target group. With this knowledge, the goal is to specify guidelines for task- and person-tailored light applications.
2. Emotion and social experience – Bringing out the best in people
   In this research line, our ambition first and foremost is developing a deeper understanding of the effects of light on spatial and social behavior and experience. For public spaces, ambitions are clearly expanding beyond ‘merely’ providing functional lighting to actively and explicitly contributing to outdoor quality. Experience in this sense is broadly defined: It includes mood, atmosphere perception, safety feelings, aggression, and crowding. We aspire to using these insights for real life applications (e.g., crowd control, ambience creation systems), fostering novel smart lighting applications through user involvement and novel business models.
   SL/L4HW is addressing two classes of challenges in this respect. The first is investigating light’s potential for managing crowds, ‘nudging’ social behavior, and improving safety.  Concrete long-term goals are claim validation of emergence egress scenarios and crowd atmosphere management. A separate but important second class of challenges pertains to the development of new value propositions for public intelligent lighting.
3. Cognition – Making day-active people smarter with diurnal light
   In this research line we are building on psychological, chronobiological and neuroscientific research, specifically and explicitly investigating effects of light on cognition and cognitive performance under natural conditions: during the day, everyday tasks, active participants. We consider both image-forming and non-image forming effects of light, and aim to close the gap between fundamental research and real-world application, to formulate meaningful and evidence–based requirements for light for cognitive performance.
   In the work domain, the trend is to move from functional environments to truly effective spaces. Here we see two high-level challenges. The first concerns specifying optimal light – determining exactly which light parameters satisfy employees’ acute and long-term lighting needs, and how these vary between persons and tasks, and with clock time. The second pertains to designing intuitive user control and the distribution of control between the user and smart systems for intelligent light systems, to optimize user and system performance, while maximizing user acceptance.
4. Health – Supporting the balance within
   In the care domain, we are moving from care environments to healing environments. Our biggest challenge here is to convincingly establish relationships between lighting on the one hand, and patient wellbeing and staff performance on the other.
   With regard to the light and health domain, our focus is on mental health (depression, burnout, self-regulation, SAD), again considering both image-forming and non-image forming effects of light, from the conviction that the light experience contributes as much to health effects as the light exposure per se. Research is geared toward understanding the relation between patterns of light exposure and dynamics of mood and stress, and includes clinical, subclinical and non-clinical populations. Adoption and adherence require our attention towards embedding healthy (ambient) lighting in the natural context: at home, at work, and in care facilities.
   In the private domain, we envisage lighting supporting a transformation from the home as a place to sleep, eat and leave to a space supportive of lifestyles. The first big challenge here pertains to exploring means to improve mental health with light. This requires that we explicitly consider 24/7 scenario design, and at the same time recognize that adoption of solutions will depend heavily on attractiveness and seamless embedding in the home context – i.e. preventing associations with ’therapy light’. Additional challenges we have recognized for the home domain are optimizing light for independent living, and designing multi-user lighting control.
5. Interaction and control
   While early generations of connected lighting have been controlled by individuals using apps on tablets or mobile phones, we foresee a future in which the lighting system is context-aware, and seamlessly and intuitively caters to both individuals and multi-user settings.
   Therefore our research, especially in the home context, focuses on intuitive controls (buttons, tangible interfaces and apps) and automatic scene setting and recommendations enabled by sensor and usage data-analytics. In addition, increasingly the lighting scenes will be determined by the activities that it supports, such as enhanced gaming, more comfortable reading, meditation, etcetera. In the office context, a similar symbiosis between context-aware sensing and intuitive controls is pursued, specifically within the Optilight project.
6. Light and building design - Integration and validation
   Ambitions in this research line come down to striking the balance: the optimization of lighting design for specific spaces and users, through integrating insights from domains of perception, emotion, cognition, health and energy to attain truly sustainable lighting. This should result in concrete recommendations for sound lighting designs.