LED Through an Optic Presented by Jason Broughton & Mike Bean
Global Organisation Carclo PLC $135 Million 1000 Employees Global Facilities Technical Plastics Precision Products Emerging Businesses 63% of Sales 37% of Sales Global Facilites UK (3) USA (5) China (2) Czech Republic (2) India (1) Automotive Specialist Lighting Antennas Aerospace - Precision Machining CIT Proprietary technology: Conductive Inkjet Printing Platform Diagnostics Microfluidic POC Testing Devices
Scotland - Harthill USA - Tuscon USA - Pennsylvania China - Shanghai
Global LED Optics Capabilities Slough, UK Global Center of Excellence for Optics Design, Development & Test Centre Advanced Manufacturing USA LED Optics Manufacturing Latrobe PA & Tucson AZ Standard & Custom Optics Engineering & Design Capability China LED Optics Manufacturing India LED Optics Manufacturing Czech LED Optics Manufacturing
Core Competencies in Optics Optical Design ASAP, Zemax, Light Tools AGi32, DIALux, Reality Roadway Tool Design & Surface Polishing Precision Moulding & Extrusion RP & Low Volume Photometric Simulation/Testing Pad & Screen Printing Coating Dip, Flow, Inkjet, UV, AR, Hard Coating In-House Assembly
Optic / Lens What is an Optic? An optic is a transparent optical lens used to converge or diverge transmitted light and to form images/spot. It is use as a secondary lens for optimal performance within a lighting application and is referred to mostly as a TIR lens.
Optic Lens What is TIR? As the angle the wave front strikes the material surface increases, the refracted light angle increases is greater until the refracted light virtually travels along the surface. At incidence angles greater than this critical angle the light can only be reflected back in to the material. This is called Total Internal Reflection, (TIR). There is no loss of optical power when this happens. Consequently Total Internal Reflection is a more efficient means of reflecting light than any metal mirror.
Principles of LED lighting with an Optic Refractive surfaces and Total Internal Reflection are used to manage the light output to produce optics with a range of beam angles. Ostar LED
Optics - Size Does Matter TIR Optics offer a range of beam angles. 6 0 10mm 18 0 9 0 20mm 30mm Source: Rensselaer Polytechnic Institute LED source chip size 1x1 mm
Optics - Shape Matters TIR Optics can have the same beam angle (FWHM) whilst offering a variety of spot patterns. Bell Shape Top Hat Shape Top hat offers: Uniformity, cut-off, light where its needed Less LED current to achieve same light level Over illuminating Required light level Lost light Same FWHM but different light distributions
Carclo Standard Optic Materials Property UNITS Polycarbonate Lexan/Makrolon Acrylic PMMA Cyclo-olefinic copolymer (COC) TOPAS Thermal conductivity W/(m K) 0.2 0.167-0.25 0.12 to 0.15 Electrical conductivity Ω/sq 10 16 10 19 10 17 Density g/cm3 1.19 1.16 1.02 Heat resistance (Max. continuous service) Degrees C 124 92 130 UV resistance - good EXCELLENT good Ageing Character - Slight yellow - uv NO VISIBLE CHANGE Slight yellow - uv Main Colour (Dyes can be added) - Clear Clear Clear Index of refraction At 589 nm n 1.586 1.491 1.526 Transmission at 589nm 3mm thick n 91 92 92 Water absorption (in water at 23 deg C) % 0.15 0.3 <0.01 Impact resistance EXCELLENT low low
Factors Affecting Injection Moulded Optical Parts Factors Affecting Geometry Possibilities Limitations Material High RI material PC Thinner Components than PMMA Improved Optical Performance Curves Too Steep TIR giving stray light and lower efficiency Electrical conductivity Large Diameter = Narrow Beam More Optical Surfaces = Controlled Light Distribution Wide Area Illumination - Bubble Diameter thickness limited by economics of injection moulding process Cost/Efficiency/Manufacturability Moulding Process Tolerances Increase Complexity Increase Cavitation Better Repeatability Better Performance Mould Size and press tonnage Longer Cycle Times Higher Tooling Costs Shrinkage vs thickness variation limits repeatability Joining Techniques Clip Features Glue Mechanical (Rivets & Screws) Tape Sonic Welding Heat Staking Through Holes may interfere with electrical circuits Low vapour pressure adhesives only Mechanical features increase part complexity Tape not as robust as alternatives Mushroom needs to be designed into space envelope
Possibilities and Limitations for Surface Treatment Surface Type Possibilities Limitations Textured Statistically Random Surface Ripple Scatter Reduced Efiiciency Angular Range +/- 20 Deg Coating Co-Extruded Surface Spin Dip Flow Inkjet Vacuum Deposition Tape Strip Material Thickness variation Across Profile Not Cost Effective for High Volume All Surfaces Coated Plugs Required for Recesses Only Single Surfaces Coated Inferior Surface Finish Only Single Surfaces Coated Only Cost Effective for High Volume Expensive Manual Set Up Light Absorption vs Cost Cost Increase
Alternative Production Technologies / Materials Technologies Advantages Disadvantages Glass Optics Higher Transmission Better surface Quality Higher Temperatures Larger Variety of Materials Good Chromatic Correction Expensive for Mass Production Heavy Brittle (Low Impact Strength) Can t Directly Add Mechanical Features Machined Plastic Optic Quick Prototype Development Diffractive Design Possible Only Acrylic, not polycarbonate... Low Volume Expensive Spun Reflectors Larger Diameters Low Cost Small Diameters Low Reflectivity
Innovation Road Map Technology Research and Development Activities TIR Lenses Over-Moulded Arrays Second Gen. Large Diameter Optics Free Form Optics Hybrid Designs (Lens & Reflector) Reflectors High Reflective Materials (White) Application Optimised Reflectors Asymmetric Designs Extrusion Larger Cross Sections Co - Extrusions Asymmetric Designs
Applications for LED Lighting Spot lighting, machine lighting Aircraft reading & colour mixing lights TV studio and stage lighting Obstruction beacons & wall washing Road & runway lighting Medical & Safety equipment Automotive: internal & external Bridge and building illumination Refrigerator & freezer lighting Domestic lighting Advertising - poster boxes
Thanks for listening... www.-optics.com LED Through an Optic Presented by Jason Broughton & Mike Bean