Document xznexGL9oGrbKmg2zjKqp7EJ

Comparison Between Existing PTFE Optical Reflectance Material and Potential Alternatives Background Optical reflectance materials are used in a variety of industries including aerospace, automotive, medical, consumer electronics, military & defense, Lighting, Image Sensors, Industrial Photonics, Cosmetics, Life Sciences, Sun Protection, and Telecommunications. The range of PTFE used in these industries varies from components to test equipment that is used to characterize the performance and determine pass/fail criteria against industry standards. These applications would fall in a new subcategory of "PEAS in Optical Applications." Performance Comparison: Reflectance The PTFE used in these applications can come in solid form as an optical reflectance standard, or as part of a spray coating that is bonded to a surface. In most cases, a high reflectance is required that has uniform, diffuse reflectance properties. If these criteria are not achieved, many of the standard industry tests cannot be realized, and the resulting uncertainty in the measurements requiring these materials will be invalid. As a comparison, the top contender for a replacement to an optical PTFE reflectance material is ceramic. The plot below compares the reflectance of optical PTFE, Ceramic, and Spray coating with PTFE material embedded in the formulation. Reflectance T1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 200 700 - Optical PTFE - Spray Coating wi PTFE - Ceramic Alternative 1200 1700 Wavelength, nm 2200 Figure 1 Comparison in optical reflectance between optical PTFE, Spray coating with PTFE, and Ceramic Alternative. As seen in the plots, the reflectance at wavelengths below 700 nm is severely reduced. This is the visible range of the human eye (380 - 760 nm) which affects the majority of the applications. Since the difference is extreme in this region, there is no practical way to overcome this deficiency with this alternative ceramic material. Report Submitted By Labsphere, Inc. Contact: Dan Scharpf, @labbsphere.com Other materials may have higher reflectance, but the ability to reflect light diffusely is limited. This optical property is critical for many applications where scattering light evenly is required and is represented by the BRDF value (Bidirectional Reflectance Distribution Function). Current optical PTFE material varies from the ideal Lambertian scattering by 5% over reflectance angles of 60. By comparison, ceramic is in error > 30% in the same range. Ideal (Lambertian) vs. Actual BRDF 0.3s000 Difference of Actual from Ideal BRDF 10.00% BRDF vs. Ideal 1/pi a 31000 0.300M) 0.29000 0_213000 0.27000 0.26000 0.25000 MO -R0 -60 .4() .20 0 20 40 60 RO Receiving Angle vs. 10 degree Incidence Optical PTFE BRDF act- too -ao 000% -40 .70 0 5.00% 10 40 SO 100 .10.00% -1500% -20_00% Receiving Angle vs 10 degree Incidence Optical PTFE BRDF Deviation from Ideal, % 100 80 0_82 120 0.22 0.3.1 Iq 0.30 LIB 0.29 - 028 027 028 Azimuthal Angle (degrees) Ceramic BRDF Polar Angle (dogmata) 20 ao so Figure 2 Comparison between Bidirectional Reflectance Distribution Factor for Optical PTFE, and Ceramic Alternative. Ideal Lambertian reflectance wouldfollow a cosine response across all reflectance angles. Report Submitted By Labsphere, Inc. Contact: Dan Scharpf, @labbsphere.com