Angle of incidence selective band pass filter for implantable chemical sensor

摘要

Apparatuses and methods for limiting the angle of incidence (AOI) of light reaching a dichroic filter. The apparatus may include an AOI filter element and the dichroic filter. The apparatus may be a sensor and may include a photodetector. The dichroic filter may be configured to prevent light having a wavelength outside a band pass region from reaching the photodetector and to pass light having a wavelength within the band pass. Physical limitations of the dichroic filter may preclude the dichroic filter from preventing high AOI light having a wavelength outside a band pass region from reaching the photodetector. The AOI filter element may be configured to prevent light having a high AOI from reaching the dichroic band pass filter and to propagate light having a low AOI to the dichroic band pass filter. The AOI filter element may be a fiber optic bundle comprising a plurality of optical fibers.

主权项

1. A sensor comprising:
a sensor housing; a graft on at least a portion of an exterior surface of the sensor housing; indicator molecules distributed throughout the graft and configured to emit emission light at least to the receiving surface of the angle of incidence filter element; a light source contained within the sensor housing and configured to irradiate excitation light to the indicator molecules; a photodetector contained within the sensor housing and configured to convert received light into current indicative of the intensity of the received light; a dichroic band pass filter contained within the sensor housing and configured to prevent light having a wavelength outside a band pass region from reaching the photodetector and to pass light having a wavelength within the band pass region to the photodetector; and an angle of incidence filter element contained within the sensor housing, comprising a receiving surface, and configured to prevent light having an angle of incidence relative to an axis perpendicular to the receiving surface greater than a threshold angle from reaching the dichroic band pass filter and to propagate light having an angle of incidence relative to the axis perpendicular to the receiving surface less than the threshold angle to the dichroic band pass filter; wherein the angle of incidence filter element is a fiber optic bundle comprising a plurality of optical fibers.