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Reflector Design Fortimo Spot Light Module. GBU LED Lamps & Systems. April 2010. Contents. Reflectors for Accent Lighting Light mixing for Fortimo SLM Reflector design rules Optical interface Optical modeling using Ray Set files Examples of Reflectors for Fortimo Spot Light Module.
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Reflector DesignFortimo Spot Light Module GBU LED Lamps & Systems April 2010
Contents • Reflectors for Accent Lighting • Light mixing for Fortimo SLM • Reflector design rules • Optical interface • Optical modeling using Ray Set files • Examples of Reflectors for Fortimo Spot Light Module
Accent Lighting luminaires • In accent lighting typically 3 beam widths are identified • Spot: 10 degree Full Width at Half Maximum • Medium: 24 degree Full Width at Half Maximum • Flood: 40 degree Full Width at Half Maximum • The light source dimensions determine the limits of the possible beam width – Law of Etendue – for certain max reflector diameters • With HID and Halogen smaller beams are possible due to the small source
Reflectors compact high intensity sourcesSource indoor guide Philips 2008
Mixing the light • Mixing the light is needed to reduce flux inhomogeneity and color variations between the individual LEDs • Options • Segmenting and faceting of reflector wall • 3D faceting • Structured reflector surface (ie diffuse) • Blurring / mixing widens the source: • Starting 12.8 mm of LED circle • After blurring 14 mm of source diameter
Diffusing the light • Diffusing the light is needed to fill the space between LEDs • Eliminates ring features in the beam • Highest efficiency is achieved when placed at the top 84% 94% 94% Specular reflector without diffuser Specular reflector with diffuser
http://www.bfioptilas.com/European+offices-3.htm Rings in the far field • A diffusion foil or structured front glass is needed to eliminate rings in the far field projection (if desired). • Options: • Diffusion foil e.g. 5° diffusing foil of Luminit™ • Structured glass • A transparent front glass with shading region at the outer edge • 1 and 2 slightly increase the beam width BeNeLux - OfficeBFiOPTiLAS B.V(Chr.Huygensweg 17-2408AJ)P.O. Box 222 2400 AE Alphenaan den RijnPhone: +31 (0)172-44 60 60Fax: +31 (0)172-44 34 14E-mail: info.nl@bfioptilas.com Anton Schotel Rings in far field Caused by direct rays
Accent factor / punch • The shape of the light distribution determines the punch • Gaussian shape is acceptable for most applications • Low height reflectors: more direct light, punch perception is reduced • FWHM ratio direct and reflected light should not be high FWHM ratio direct/reflected light: 2.7 FWHM ratio direct/reflected light: 5.5 Large quantity of direct light, large FWHM of direct light
Typical reflector design limits (Source 1100 lm and 14mm) • Beam angle (FWHM) for certain reflector diameter is limited by law of Etendue, peak intensity is limited by reflector diameter and average source luminance • Using Gaussianbeam profile, an acceptable punch perception is achieved for the white shaded area Typical minimal beam width for 1100 lm module is ~15o FWHM
Typical reflector design limits (Source 2000 lm and 20mm) • Beam angle (FWHM) for certain reflector diameter is limited by law of Etendue, peak intensity is limited by reflector diameter and average source luminance • Using Gaussianbeam profile, an acceptable punch perception is achieved for the white shaded area Typical minimal beam width for 2000 lm module is ~20o FWHM
Light Output Ratio vs reflector dimensions • The reflector Light Output Ratio (LOR) or efficiency decreases for higher reflectors due more reflections at the reflector wall. • White shaded area depicts acceptable punch • No front glass taken into account 1100 lm 2000 lm
Typical reflector designs • Table with typical reflector performances • Based on modeling, including mixing/diffusive impact, no front glass, Reflector R = 90%
Reflector technologies • Reflector technologies, price points, typical reflectivity • Final reflector efficiency (LOR) depends on reflector shape
Area for reflector mounting Minimal distance of metallic reflector to electrical components is 1.2mm in open air, the cover ensures that this distance is met Optical interface
Optical interface • The surface available for reflector mounting is a ring with width: • 1100 lm: 7.3 mm • 2000 lm: 4.8 mm Any 2000lm reflector will fit on the 1100lm module as well y x
Optical interface reflector attach • Options for reflector attachment: • Mount to housing • Mount to heat sink • Glue to module • Using an additional bayonet on module Option for reflector mounting with additional metal component
Ray Sets 1100/2000 modules for reflector design • Available formats for customer use • Measurement method • SIG 300, Radiant Imaging, flux measured is relative flux, including color
Intensity polar plot 1100 & 200 Lm SLM Fortimo SLM 1100lm Alignment Image Cross section of the CAD-model • The coordinate system of the ray set is identical to the coordinate system of the CAD-file: ‘Fortimo_LED_SLM_1100_18W-8xx_wk10.stp. If you import both the ray set and the CAD-file to the same location they are aligned. • To achieve this the following rotation and translation was performed: • Rotation about Z-axis: -1° • Translation along X-axis: 0.10mm • Translation along Y-axis: 0.01mm • Translation along Z-axis: -0.4mm (determined by defocus-analysis in LightTools) • The origin of the coordinate system is now in the center of the module at the height of the LED dies. • Part of the light is blocked by the module cover in the measurement. This part is missing in the ray sets (see cross section). • The rays start on a cylinder above the LEDs, so no rays start inside the geometry (radius = 9.4mm, 1.491mm < z < 1.5).
Intensity polar plot Fortimo SLM 2000lm Alignment Image Cross section of the CAD-model • The coordinate system of the ray set is identical to the coordinate system of the CAD-file: Fortimo_LED_SLM_2000_33W-8xx_wk10.stp. If you import both the ray set and the CAD-file to the same location they are aligned. • To achieve this the following translation was performed: • Translation along Y-axis: -0.1mm • Translation along Z-axis: -0.6mm (determined by defocus-analysis in LightTools) • The origin of the coordinate system is now in the center of the module at the height of the LED dies. • Part of the light is blocked by the module cover in the measurement. This part is missing in the ray sets (see cross section). • The field of view of the SIG300 is too small for the module. Therefore, part of the indirect light is missing in the ray sets (see alignment image). • The rays start on a cylinder above the LEDs, so no rays start inside the geometry (radius = 11.9mm, 1.491mm < z < 1.5).
Prototype results 1100 lm module + SLS reflector 5° diffuser foilfromLuminitTM Uniform spot, no rings Reflector efficiency: 86 – 90% Including POC foil: 82 – 85 % Lineair scaling Log scaling Δu’v’ <0.008 for values larger than 5% of peak intensity
Prototype results 1100 lm module + SLS reflector 20° diffuser foilfromLuminitTM Uniform spot, no rings Lineair scaling Log scaling Δu’v’ <0.008 for values larger than 5% of peak intensity
Prototype results 2000 lm module + SLS reflector 10° diffuser foilfromLuminitTM FWHM 26° Reflector efficiency: 86 – 90% Including POC foil: 82 – 84 % Δu’v’ < 0.006 within 10% of peakintensity Δu’v’ < 0.008 within 5% of peakintensity Visual appearance(log2 visualisation)
Reflector supplier Jordan http://www.jordan-reflektoren.de • Jordan developed three reflector types that fit both 1100 and 2000 lm modules with a click-fit onto the module • Example beam profiles 1100 lm, 2 x 12.2O 2000 lm, 2 x 13.7O Need diffusing exit window
Reflector supplier Alux-Luxar http://www.alux-luxar.de • AluxLuxar is developing a series of reflectors • Both pre-anodized (Miro) and post anodized • Example of Miro 8 based reflector for 1100 lm • Efficiency > 90% No diffuser 1o diffuser Reflector in combination with 5o diffuser gives a Gaussian beam, FWHM < 15°. 5o diffuser Efficiency: -3% / 1100 lm
Convergent beams - cross over reflector • By combining the Fortimo SLM module and a convergent reflector, a system with an aperture can be designed • The efficiency of the system is limited by the Law of Etendue • Example for an aperture 30 mm and desired FWHM = 2x12o : • 2000 lm module with 20 mm efficiency: 11% • 1100 lm module with 14mm efficiency: 20% • With a hypothetical source of 6.5 mm: efficiency: 100% 1100 lm module