Frequently Asked Questions
 
1. What is the transmission of your LSD diffuser?
A. Since our technology is based on diffractive micro-structures the transmission efficiencies of our diffusers are very high, 88-92% depending on the angle. Smaller angle diffusers have the highest transmission.
 
2. What does FWHM mean and how do you measure it?
A. FWHM is an abbreviation for Full Width Half Maximum angle of diffusion a collimated laser would see after passing through the diffuser. A 10° diffuser will produce a beam width of 10°. When used with divergent sources like LEDs which have an angle of divergence (ά), the resultant angle of diffusion (β ) can be estimated using the following equation: β =√(ά2 + Δ2) , where Δ is the angle of the diffuser).
 
3. Is the angle of diffusion and transmission wavelength dependant?
A. Since our micro-structures are random and non-periodic it is not wavelength dependant, so it works well from 400nm to 1500nm.
 
4. Should I face the diffuser towards or away from the light source?
A. The diffuser has improved transmission  characteristics if the micro-structure side is facing the light source, but it has better source hiding characteristics if the microstructure side is facing away from the light source.
 
5. How should I handle the diffuser and can I clean it if gets dirty?
A. We suggest you handle the diffuser with clean latex gloves. High angle diffusers are very prone to damage due the height of the micro-structures. They can be cleaned carefully using optical wipes and ethanol.
 
6. How do I mount the diffuser in my system?
A. We recommend you find a mechanical means of securing the diffuser into your system, for example using the natural tension of a film on curved surface. We offer pressure sensitive adhesive (PSA) as an option but this process is difficult and you may experience the incorporation of air bubbles during the lamination process.
 
7. What substrates and thicknesses are the diffusers available in?
A. We provide thin film and rigid versions of our diffusers in polyester, polycarbonate, acrylic and glass. Please see the Download section for our catalog.
 
8. Does the angle of diffusion or transmission change with I use a thicker diffuser?
A. No, since our technology is based on a surface relief pattern these parameters are not dependant on the thickness of the substrate.
 
9. What is the effective working distance of the diffuser to eliminate hotspots under direct view?
A. This depends on the angle of divergence and spacing of the light sources. With 110° Field of View surface mount LEDs the relationship is around 1:1.  That is, if the LEDs are spaced 1 inch apart then you will need a little more than 1 inch distance from the LEDs to our largest angle diffusers (80° or 75°x45°).
 
10. Do you have evaluation kits we can use to determine which angle will work for me?
 A. Yes, please see our sample order form section. We have a 9 piece kit with 1” samples and larger A4 sized sheets of select single angles on 0.010” thick polycarbonate .
 
11. Can the LSD diffuser replace a secondary optic?
A. No.  The LSD diffuser cannot decrease the divergence of a light source, it can only increase its angle of divergence.