Patent ID: 7507964

Claim:
An electro-optical viewing device, comprising: a light filtering system including a first light filter sub-system positioned at a light-input end of the device and a output sub-system distinct from the first light filter sub-system and positioned at a light-output end of the device, wherein each of the first filter sub-system and the output sub-system are configured and arranged so as to form two light channels each light channel having a transmission characteristic defining the boundaries of the light channel with respect to wavelength; wherein the first filter sub-system is further configured and arranged so the transmission characteristics that define the two light channels of the first filter sub-system, cross each other at a predetermined point, where the predetermined point at which the transmission characteristics for the two light channels cross each other lies in a range of wavelengths from about 580 nm to about 620 nm; and wherein each of the first filter sub-system and the output sub-system are configured and arranged so as to form only two light channels.