Birefringence measurement of polymeric films and the like
AssigneeHinds Instruments, Inc.
InventorBaoliang WANG
Life of this patent
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Abstract
Provided are methods for determining the birefringence level of optical material such as polymeric film. In one embodiment, the method uses a setup of optical components that has known system reference angle. The sample may be a stretched polymeric film that has a fast axis angle that has a predetermined orientation in the sample. The system is operated to align the direction of the fast axis of the sample with the reference angle of the system and to measure the birefringence level at a location of the sample. As one aspect of the invention, embodiments and methods are described for accurately determining birefringence levels across a very wide range and up to tens of thousands of nanometers.
Claims23
A method of determining the birefringence level of a sample of optical:
- material using a setup of optical components that has a known system reference angle, wherein the sample has a fast axis angle having a predetermined orientation in the sample, the method comprising the steps of:
- aligning the direction of the fast axis of the sample with the reference angle of the system;
- and
- measuring the birefringence level at a location on the sample.
A system for measuring birefringence levels in a sample of optical material that has a fast angle axis with a known orientation, comprising:
- a source of two or more beams of light having respective first and second wavelengths that are different from one another;
- a polarization modulator for modulating the polarization of the light beams;
- a sample support for supporting the sample with its fast axis angle at a predetermined orientation;
- and
- measurement means for directing the beams through the sample and calculating the birefringence level of the sample.
Dependencies are inferred from the claim text.