"Light: from Simple Optics to Amazing Applications"
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"Light: from simple optics to amazing applications" Andrzej Kotlicki, Alex Rosemann and Helge Seetzen The Structure Surface Physics Laboratory Faculty: Dr. Lorne Whitehead (In charge of the lab and the inventor) Dr. Andrzej Kotlicki RA: Dr. Michele Mossmann Post Doctoral Fellows: Dr. Alexander Rosemann and Dr. Yasser Abdelaziez. PhD student Helge Seetzen (also Chief Technology Officer of Brightside Technologies) Graduate Students and Undergraduate researchers Outline • Geometrical optics reminders: reflection, refraction, Snell’s Law, Total Internal Reflection (TIR) • Applications of TIR: fiber optics, retro-reflectors, guiding film • Frustrated TIR – applications to “real” black and white reflective display. Electronic paper? • New Developments in Solar Lighting Systems based on Prism Light Guides will be presented by Alex Rosemann • New concept of electronic display – High Dynamic Range Display from our Spin-off company Brightside Technologies - will be presented by Helge Seetzen • Ray model of light. • When we can use it? • Wavelength of light 0.4 - 0.6µm Snell’s Law: When light passes from the medium with refraction index n1 into another with refraction index n2: n1sin(θ1) = n2sin(θ2) n2 1 1 1 1.6 1.6 1.6 n 1 0º Slide by Lorne Whitehead n2 1 1 1 1.6 1.6 1.6 n 1 10º Slide by Lorne Whitehead n2 1 1 1 1.6 1.6 1.6 n 1 20º Slide by Lorne Whitehead n2 1 θ t ⎛⎛ n ⎞ ⎞ 1 −1 1 θθri== θ tsin⎜⎜ ⎟ sin() θ i⎟ 1 ⎝⎝ n2 ⎠ ⎠ 1.6 1.6 Snell’s Law 1.6 θi θr n 1 20º Slide by Lorne Whitehead n2 1 ⎛⎛ n ⎞ ⎞ 1 −1 1 θθri== θ tsin⎜⎜ ⎟ sin() θ i⎟ 1 ⎝⎝ n2 ⎠ ⎠ 1.6 1.6 Snell’s Law 1.6 n 1 20º Slide by Lorne Whitehead n2 1 ⎛⎛ n ⎞ ⎞ 1 −1 1 θθri== θ tsin⎜⎜ ⎟ sin() θ i⎟ 1 ⎝⎝ n2 ⎠ ⎠ 1.6 1.6 1.6 n 1 30º Slide by Lorne Whitehead n2 1 ⎛⎛ n ⎞ ⎞ 1 −1 1 θθri== θ tsin⎜⎜ ⎟ sin() θ i⎟ 1 ⎝⎝ n2 ⎠ ⎠ 1.6 1.6 1.6 n 1 38.682º Slide by Lorne Whitehead n2 1 1 θr =θi θt = no answer! 1 1.6 1.6 1.6 n 1 38.683º Slide by Lorne Whitehead n2 1 1 θr =θi θt = no answer! 1 1.6 1.6 1.6 n 1 50º Slide by Lorne Whitehead n2 1 1 θr =θi θt = no answer! 1 1.6 1.6 1.6 n 1 60º Slide by Lorne Whitehead n2 1 1 θr =θi θt = no answer! 1 1.6 1.6 1.6 n 1 70º Slide by Lorne Whitehead Critical angle •n1sin(θ1) = n2sin(θ2) • θ2 = 90º -1 • θ1 = sin (n2 /n1 ) •For water θ1 = 49º • For glass θ1 = 42º Fiber Optics • Fiber optics for communication Fiber Optics Endoscopes Guiding film 3M Optical Lighting Film (OLF) Micro-replicated light guiding film uses linear 90 degree prisms Samples Rainbow Reflective side Transparent side Image deformations air n1 = 1 Prismatic Film n2 =1.6 air n1 = 1 The critical angle for total internal reflection is -1 αc = sin (n1/n2) = 38.7°. The angle of incidence, 45°, is larger than critical, therefore a total internal reflection occurs and the light is reflected at the angle 45°. The same happens on the second face, so the light is send back and leaves the film at 180° to the original direction. air n1 = 1 Prismatic Film n2 =1.6 air n1 = 1 The light comes from the medium with a smaller so there is no total internal reflection. The refracted angle is -1 αr = sin (sin(45°)n1/n2) = 26.2°. The incidence angle on the bottom surface is 45 - 26.2 = 18.8 which is less than critical angle so there in no total internal reflection and we have an other refraction: -1 αr2 = sin (sin(18.8°)n2/n1) = 31°. Retro-Reflection Light undergoing 1- 3 reflections from a corner cube with the inner reflecting surfaces returns at 180 degree to the incident light - “retro-reflection”. 3M Diamond GradeTM Reflective Sheeting An array of corner cubes forms retro-reflective sheet material The prism light guide McDonald’s Roof Beam Light Guide System Vertical Light Guides 3M Bldg. 275 St. Paul, MN Light Guide Illumination of Boston’s Callahan Tunnel Highly directional down lighting from new Light Guides and Sulfur Lamps in Smithsonian Air and Space Museum Solar Lighting Systems based on Prism Light Guides • Long History • New Developments will be presented by Alex Frustrated TIR – applications to “real” black and white reflective display. Electronic paper? TIR... air gap glass glass TIR... glass glass Frustrated TIR glass glass Principle of a TIR-based Reflective Display light ray is light ray is reflected absorbed micro-prisms (n1) gap (n2) absorptive material “White State” “Black State” Electrophoresis • Controlled motion of charged particles in a medium in response to an applied electric field d + - - + - - + - electrophoretic mobility: µ - + - + + - + + - V Slide by Michele Mossman d + - - - + + - - µV - + - + Particle velocity: ν = + d + - + - V Slide by Michele Mossman d + - - - + + - - - + - + + + - + - V Slide by Michele Mossman d - + - - + + - - + - - + + + - + - V Slide by Michele Mossman d - - + - + + - - + - - + + + - - + V Slide by Michele Mossman Electrophoretic TIR Display ON STATE O FF STATE High Index Retro-reflective Surface V Electrophoretic Suspension Slide by Michele Mossman CLEAR Electronic Paper Conventional LCD Non-switching Display Demonstration Of TIR-based reflective display The TIR-based reflective display has an image quality very similar to printed white paper. Slide by Michele Mossman Hemispherical Microstructures reflected light rays bright annulus dark center Slide by Michele Mossman Hemispherical Microstructures Microstructured surface high density pigment suspension Slide by Michele Mossman New concept of electronic display – High Dynamic Range Display from our Spin-off company Brightside Technologies - Helge Light: from simple optics to amazing applications The Solar Lighting Project at UBC Alexander Rosemann February 18, 2006 Solar Lighting Project – Project Partners • Korea Institute of Energy Research, Taejon, Korea • Natural Resources Canada, Ottawa, ON • University of British Columbia Vancouver, BC Motivation for daylight utilisation In Vancouver, daylight is available during 94 % of the working hours Project Aim • Daylight Utilisation in Deeper Building zones • Use of materials that are potentially low-cost in mass production • Demonstration of the system in a portable test environment • Demonstration of the system in a real building •… Basic Idea Solar Canopies Example building cross section with solar canopies on south-facing wall feeding prism light guides UBC Solar Lighting Project Control Unit Adaptive Sun Helio- TFL + Butterfly Light box el. Array Guide ballasts Solar Canopy Hybrid Prism Light Guide Portable Testroom Heliostat design Sun positions in Vancouver Adaptive Butterfly Array Adaptive Butterfly Array – April 21st 91011noon12 ampm am Canopy System mirror array mirror array M 2 Fresnel lensi or Fresnel lens rro irr r 2 M M 1m ir r 1 ror rro 1 Mi 3m Light pipe Prism Light Guide Fluorescent Lamps Extractor Highly reflective film Microprismatic film Portable testroom South Wall Redirecting the direct sunlight with the Adaptive Butterfly Array Measurement Overview • Artificial Lighting • Daylighting • Daylight entering through the South window • Daylight entering through the solar canopy system What did we measure? Illuminance (Luminous Flux / Area), measured in lx Measuring height: 0.8 m What are the target values? Recommendation in office buildings: 500 lx on the task area and 300 lx in surrounding areas Artificial lighting dimming characteristics Illuminance distribution for a right dimming voltage of 10 V centr e The relative illuminacne distribution does not change left with dimming. 12345678 0-500 500-1000 1000-1500 Dimming Characteristics The mean illuminance varies 1400 with the dimming voltage as x 1200 shown in the figure. 1000 800 This data is useful for the 600 control algorithm 400 200 Mean Illuminance in l 0 02.557.510 Dimming Voltage in V Daylighting measurements 1 Setup: SOUTH WALL uncovered Hybrid light guide blocked E = 527 lx 2000 right 1500 1000 centre 500 Illuminance in lx 0 left 12345678 02468 measurement point # 0-500 500-1000 1000-1500 1500-2000 Illuminance distribution Illuminance along the centre line The illuminance is very non-uniform. Although the mean illuminance is above 500 lx, the values drop below 500 lx in the second half of the room. For this scenario artificial lighting is required all the time. Daylighting measurements 2 Setup: SOUTH WALL covered Hybrid light guide open E = 550 lx 11:08 am TLT 1000 800 right 600 400 centre 200 Illuminance in lx 0 left 12345678 02468 measurement point # 0-200 200-400 400-600 600-800 800-1000 Illuminance distribution Illuminance along the centre line The mean illuminance is above 500 lx, the values are well above 500 lx in the centre line, even in the second half of the room. For this scenario artificial lighting is not required. Combined Daylighting Results Setup: SOUTH WALL open Hybrid light guide open E = 1094 lx Simulated results 2500 right 2000 1500 1000 centre Illuminance in lx 500 0 left 02468 12345678 measurement point # 0-500 500-1000 1000-1500 1500-2000 2000-2500 combined window only Illuminance distribution Illuminance along the centre line The mean illuminance is above 500 lx, the values are well above 500 lx in the centre line, even in the second half of the room. For this scenario artificial lighting is not required. Illumination in deeper building zones Thank you for your attention The Solar lighting project at UBC Luminous Transmittance of the optical lighting film High Dynamic Range Imaging Pipeline Helge Seetzen February, 2006 Imaging Pipeline – 8-bit rules! 2/18/2006 ©2005 Brightside Technologies Inc. 2 Image Quality – What are we missing? Human Overall Luminance Vision Range (14 orders of magnitude, scale in log cd/m2) -6 -4 -2 0 2 4 6 8 starlight moonlight indoor lighting sunlight Human Simultaneous 5 orders Luminance Vision Range of magnitude 2-3 Today’s Devices orders 5 orders BrightSide Technologies of magnitude 2/18/2006 ©2005 Brightside Technologies Inc.