Definition of Baseline Lens Material
The Mitsubishi-000 ultra pure UVT-PMMA is the current baseline lens material.
The dispersion of the index of refraction is lower compared to other samples of UVT-PMMA.
The transmittance in the wavelength region 330 - 400 nm is higher compared to standard UVT-PMMA.
Definition of Baseline Lens Material
UVT-PMMA Refractive Index
1.461.48
1.51.521.541.561.58
320 340 360 380 400
Wavelength (nm)
Ind
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of
Re
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CI
000
Definition of Baseline Lens Material
Definition of Baseline Lens Material
Definition of Baseline Lens Material
The requirements of the optical sub-system have identified two design goals for the lens material:
The absolute value of the dispersion of the index of refraction must satisfy, Δn 0.0012, in the wavelength interval 330-400 nm.
The transmission must be equal to or greater than the values: 97% at 400 nm, 95% at 360 nm, and 92% at 330 nm for a thickness of 10 mm.
Definition of Baseline Lens Material
PMMA Measurement
Optical Properities Value Units Procedure/Conditions
dN/dT - change in index of refraction with temperature 1.05E-04 /ºC
dN/dl - change in index of refraction with wavelength nd=1.491
UV Light Transmission (bulk material) 92 % 400 nm, 3 mm plate
Mechanical Properties
Coefficient of Thermal Expansion 8.00E-05 / oC
Density 1.19 - 1.20 g/cm3
Tensile Strength at the Yield Point 650 -730 kg/cm2
Ultimate tensile strength 387-642 kg/cm2
Thermal Conductivity 4.96E-04 cal/cm/sec/oC
Young's Modulus of Elasticity 3.16E+04 kg/cm2 ASTM D 638 (ISO 527-1)
Glass Transistion Temperature Range 105 - 120 oC
Water Absorbency 0.3 % Measured at 60oC
Definition of Baseline Lens Material
Allow the manufacturer the freedom to achieve these two goals by varying other physical parameters such as the index of refraction, and the density.
One an example of this approach is the partial fluorination of UVT-PMMA.
Outer cladding of double clad optical fiber Kuraray Plastics, Inc. (n = 1.42) NRL Chemistry Division ( n = 1.437)
Note: Fully fluorinated co-polymer CYTOP (n = 1.34) has a density of 2.0 g/cm3.
Definition of Baseline Lens Material
U.S. Plastic Manufacturers: Reynolds Polymer Technology, Inc.
Gained experience fabricating the acrylic containment vessel as part of the Sudbury Neutrino Observatory (SNO) experiment.
Can manufacture 3 m X 3 m lens blanks. Spartech/Polycast (2 m X 2 m lens blanks) CYRO Industries (Maximum thickness 1 inch)
Japanese Plastic Manufacturers: CI Industry Co. (Non-additive UVT-resin) Mitsubishi (000) Asahi Glass (Fluoropolymers, CYTOP)