Light & Health - Design Strategies & Technologies...Light & Health - Design Strategies &...
Transcript of Light & Health - Design Strategies & Technologies...Light & Health - Design Strategies &...
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Light & Health - Design Strategies & Technologies February 12, 2015
Konstantinos Papamichael, Ph.D. Professor, Department of Design Co-Director, California Lighting Technology Center University of California, Davis
The Main Source of Light & Life
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The Sun
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Spectral Distribution of Sunlight
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The Electromagnetic Spectrum
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Daylight Spectral Power Distributions
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The Dynamic Nature of Daylight
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Daylight Spectral Power Distributions
8http://www.handprint.com/HP/WCL/color1.html
Daylight Correlated Color Temperature (CCT)
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http://www.lrc.rpi.edu/programs/nlpip/lightinganswers/fullspectrum/comparisons.asp
Human Evolution - Sunrise
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Human Evolution - Daytime
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Human Evolution - Sunset
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Human Evolution - Night
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Human Evolution - Light at Night
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Human Evolution - Light at Night
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Visual & Circadian Pathways
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1. Visual Pathway
– Light stimulates the cerebral
cortex for vision & perception
2. Biological Pathway
– Light causes messages
along a biological pathway
(Hypothalamus, Pituitary,
Pineal Gland) that are used
to regulate the body’s
autonomic nervous and
endocrine systems
Human Eye Anatomy
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Cornea!Aqueous Humor!
Pupil!
Iris!
Ciliary Muscle!Sclera!
Fovea!
Retina!
Optic Nerve!
Vitreous Humor!
Eyelens!
Choroid!Suspensory ligament!
Retinal Structure
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Rods (Rhodopsin) & Cones (Photopsins)
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Photopsin & Rhodopsin Sensitivities
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http://www.handprint.com/HP/WCL/color1.html http://hyperphysics.phy-astr.gsu.edu/hbase/vision/bright.html
ipRGC (Melanopsin) intrinsically photosensitive Retinal Ganglion Cell
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• Photo pigment
• Specialized ganglion cells
• Biological path
• Circadian rhythms
• Pupillary reflex
• Specialized ganglion cell
• Many & long tentacles
• Melanopsin photopigment
• Biological path
• Circadian Rhythms
• Pupillary (+?) control
Adaptation Mechanisms
• Mechanical change: pupil diameter
– Admits varying amounts of light
– Factor of about 5%
• Photochemical change: changing amounts of photo pigments available
– Bleaching makes less pigment available
– Factor of about 1000%
• Neural change: changing synaptic interaction
– Lower overall neural sensitivity as light level increases
– Factor of about 1000%
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Photopic, Scotopic & Circadian Sensitivities
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Circadian Rhythms
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• Endogenous (self-sustained) rhythms • From the Latin
– “circa” = approximately – “dies” = day
• Have been observed even in single celled organisms including prokaryotes, e.g,. bacteria
• Major Biological Effects – Hormone Excretion
• Melatonin - sleep-wake cycle • Insulin - carbohydrate metabolism • Cortisol - blood pressure & sugar levels
– Body Temperature – Cognitive performance – ...
Melatonin & Cortisol Circadian Rhythms
Incandescent Spectral Power Distribution
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Pros & Cons of Incandescent Lighting
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• Pros – Excellent color rendering - 100 CRI – Excellent for well-being & health - low blue content – Excellent dimming - smooth, further reducing blue content – Excellent drama - sharp shadows – No flicker! – No noise! – Low cost
• Cons – Low luminous efficacy
Fluorescent Lighting CCT (K)
2700 3000 3100 3500
3500 4100 5000 6500
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Fluorescent Spectral Power Distribution
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Natural Daylight
Incandescent Daylight Fluorescent
Cool White Fluorescent Tri-Phosphor 3500K
Metal Halide
Spectral Power Distributions
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Photopic Illuminance: 2 fc - Scotopic Illuminance: 200+ fc
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UC Davis Medical Center Sign
Photopic, Scotopic & …Cirtopic? Lumens
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2
200
?
Blue-rich Light at Night
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American Medical Association - June 2012
Light Pollu+on: Adverse Health Effects of Nigh;me Ligh+ng Report 4 of the Council on Science and Public Health (A-‐12) of the American Medical Associa/on
Biological adapta+on to the sun has evolved over billions of years.
The power to ar+ficially override the natural cycle of light and dark is a recent event and represents a man-‐made self-‐experiment on the effects of exposure to increasingly bright light during the night as human socie5es acquire technology and expand industry.
Among the la;er (health effects) are poten5al carcinogenic effects related to melatonin suppression, especially breast cancer. Other diseases that may be exacerbated by circadian disrup5on include obesity, diabetes, depression and mood disorders, and reproduc+ve problems.
Due to the nearly ubiquitous exposure to light at inappropriate +mes rela+ve to endogenous circadian rhythms, a need exists for further mul+disciplinary research on occupa5onal and environmental exposure to light -‐at-‐night, the
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Blue-rich LED & Circadian Sensitivity
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Key Lighting Design Strategies for Health
• Reduce exposure to blue light during the night – Outdoor lighting
• Luminaires • Signage
– Indoor lighting - especially residential • Luminaires • Televisions • Computer displays
• Increase exposure to blue light during the day – Daylight! – High CCT light sources for applications that need it
• Offices • Schools • Work spaces • Assisted living housing
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Implementation Strategies & Technologies• Outdoor Lighting
– Occupancy-based bi-level lighting • Single Source
– Full output during occupancy – 50% or less during vacancy (10% - 20% is enough)
• Dual Source – High level Low CCT white light during occupancy – Low level Amber or Amber-Red LED during vacancy
• Indoor Lighting – Nighttime
• Low CCT (less than 3,000k) • Low level Amber or Amber-Red LED for nightlight
– Kitchen – Bathroom – Way finding
– Daytime • Daylight! • High CCT lighting - for applications that need it
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High CCT Lighting for Offices & Schools
• Mills, Peter R., Tomkins, Susannah C. and Schlangen, Luc JM. “The effect of high correlated colour temperature office lighting on employee wellbeing and work performance.” Journal of Circadian Rhythms, 11 January 2007, pages 2-5.
• High CCT Electric Lighting in Call Center with Shift Work
• Reduced fatigue (26.9%) • Increased alertness (28.2%) • Reduced daytime sleepiness (31%) • Increased work performance (19.4%) • Increased vitality (28.4%) • Increased mental health (13.9%)
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Melatonin Suppression
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Brainard, George C. “Action Spectrum for Melatonin Regulation in Humans: Evidence for a Novel Circadian Photoreceptor.” The Journal of Neuroscience (2001): 6405-411. Web. 29 Apr. 2013.
Monochromatic LED Spectra Manufacturer A
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400 550
400 550
Monochromatic LED Spectra Manufacturer B
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446 477
Effective
Most Effective
Bathroom Light Switch with Occupancy Sensor & Amber LED Night Light
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Dual Source Bi-level Outdoor Luminaire
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Amber LED & Induction Lighting
Dual Source Bi-level Outdoor Luminaire
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Occupancy Mode
Dual Source Bi-level Outdoor Luminaire
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Vacancy Mode
Indirect Downlight Prototypes
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Dual Source Kitchen Lighting
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Full Light Output Night Lighting - Amber LEDs
Spectrally Tunable Lighting for Office Spaces
• Laboratory Prototype • Independent control of
– Intensity – CCT
• Change CCT maintaining Intensity • Change intensity maintaining CCT
WA
RM
NE
UTR
AL
CO
OL
100% 50% 25%
Refrigerator Lighting
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White Light Amber Light
HONDA ZNE House, UC Davis
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Honda House - First Floor Amber LED Way Finding Night Lighting
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Honda House - Second Floor Amber LED Way Finding Night Lighting
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Bathroom & Kitchen Lighting
Amber LED “Toe-Kick” Night Light
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Amber LED “Toe-Kick” Night Light
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Kitchen Amber LED Night Lighting
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Kitchen High & Low Amber LED Night Light
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Living Room - High & Low Ambient Lighting
Corridor Lighting
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Stairwell & Corridor Night Lighting
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De Young ZNE House, Fresno, CA
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Bathroom Lighting
Kitchen Lighting
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Corridor Lighting
Maximizing Health & Sleep in the Elderly LD+A Article by Kimberly Mercier
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Philips “Heu” Screw-based Lamp
66DigitalTrends.com
Wireless Base - Hardwired to Wi-Fi Router
67DigitalTrends.com
“Relax” Setting
68DigitalTrends.com
“Concentrate” Setting
69DigitalTrends.com
“Reading” Setting
70DigitalTrends.com
Philips “Hue” Screw-based Lamps
71DigitalTrends.com
6000K, 100fc average 3500K, 50fc average 2900K, 50fc average
Photo credit: Philips
5000K -‐ Focus/Concentrate 6500K -‐ Wake Up/Morning 4000K -‐ Group Ac5vity 3000K -‐ Relax
Philips Circadian Lighting for Classrooms
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12000K, 65fc average
Samjin Color-Tunable Lighting
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50%
100%
2700K 4000K 6500K
BRIG
HTNESS
CCT
SAMJIN
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