OPTICAL MODULATION LIQUID CRYSTAL ELEMENT AND VARIABLE OPTICAL ATTENUATOR

• Main Author: OI YOSHIHARU
• Format: Patent
• Language: English
• Published: 17.12.2009
• Subjects: DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF

PROBLEM TO BE SOLVED: To provide an optical modulation liquid crystal element capable of adjusting light quantity stably and quickly over a wide wavelength range in accordance with an application voltage irrespective of a polarization state of incident light, and to provide a variable optical attenuator. SOLUTION: The optical modulation liquid crystal element includes: a polarization separating element which deflects light of first linear polarization and light of second linear polarization by the same angle in axially symmetrical directions to each other with respect to polarization components of the first linear polarization and the second linear polarization vertical to each other of the incident light, on the basis of the light axis of incident light; and a reflection type liquid crystal element in which the polarization states of transmission light of the first linear polarization and the second linear polarization are changed in accordance with the application voltage. The reflection type liquid crystal element includes a polarization modulation element and a reflective layer, wherein the polarization modulation element is such a liquid crystal cell that a liquid crystal layer is sandwiched between substrates each having an electrode, and retardation value changes in accordance with the voltage applied between the electrodes. The optical modulation liquid crystal element is characterized in that the polarization separation element, the polarization modulation element and the reflective layer are arranged in the order from the incident light side. COPYRIGHT: (C)2010,JPO&INPIT