Patent ID: 9207516
Filing Date: 2015-12-08
Classification: G02F

Abstract:
1. A hybrid tunable filter, comprising: an upper substrate comprising an upper lip; a lower substrate comprising a lower lip and being substantially parallel to the upper substrate, wherein the upper substrate and the lower substrate are offset from each other to allow the upper lip to hang over the lower substrate and the lower lip to protrude outside of the upper substrate; a first conductive layer coated on a lower surface of the upper substrate; a second conductive layer coated on an upper surface of the lower substrate; a first high reflectivity layer formed on a portion of the first conductive layer; a first electrode layer formed on a portion of the first conductive layer under the upper lip; a second high reflectivity layer formed on a portion of the second conductive layer; a second electrode layer formed on a portion of the second conductive layer above the lower lip; a spacer sandwiched between the upper substrate and the lower substrate, wherein the spacer is elongated and is arranged to form a loop defining a gasket enclosed area; a liquid crystal material configured to fill the gasket enclosed area, wherein the first high reflectivity and the second high reflectivity layer define an etalon cavity in the gasket enclosed area which transmits light characterized by multiple spectral peaks, wherein the multiple spectral peaks of the light in the etalon cavity are separated by a free spectral range FSR; and a band-pass filter layer formed on one of the upper surface of the upper substrate or the lower surface of the lower substrate, wherein the band-pass filter layer has a single pass band, wherein the band-pass filter layer is characterized by a band-pass width BPW larger than 0.5 FSR and is configured to pass the light in one of multiple spectral peaks from the etalon cavity, thereby producing an output light having a single spectral peak.