Patent ID: 7253896
Filing Date: 2007-08-07
Classification: G01J,G01N

Abstract:
1. A filter for use in a spectrometer, the filter being arranged to filter radiation transmitted by a sample, the filter comprising: a first polarizer for polarizing the radiation transmitted by the sample; a birefringent element responsive to an applied signal, wherein the birefringent element modifies the polarization of the polarized radiation in accordance with the wavelength of the radiation and the applied signal; and, a second polarizer for polarizing the radiation transmitted by the birefringent element, the radiation being transmitted in a transmission direction, characterized in that the birefringent element comprises: a birefringent member having a first birefringence, the birefringent member being responsive to a force applied thereto to generate an additional second birefringence; and, a driver for applying a force to the birefringent member in accordance with the applied signal, and the driver comprises a piezoelectric member coupled to the birefringent member on one end or at two opposite ends.