| 摘要 |
PROBLEM TO BE SOLVED: To realize a voltage-variable optical attenuator from which a stable and high optical quenching ratio can be obtained. SOLUTION: This liquid crystal element 100 consists of a liquid crystal cell 110 and a phase plate 120. The cell 110 is formed so that a liquid crystal layer 1 is interposed between translucent substrates 5, 6 provided with transparent electrodes 3, 4 respectively and has the retardation value changing from R1 to R2 with respect to the linear polarized light of λ wavelength which is made incident to the cell 110 and passes through the cell 110 when the voltage of V1 to V2 (V1 ≠V2 ) is applied between the electrodes 3 and 4. The retardation value R of the plate 120 is Rv satisfying R1 >=Rv >=R2 and satisfies R+Rv =λ with respect to the linear polarized light of λ wavelength. This optical attenuator is obtained by preparing the element 100 and furthermore arranging a polarizer on the light entering side or the light exiting side of the element 100. |
