735nm Bandpass Filter

Context: This patent describes the fabrication of high-performance, multi-cavity optical filters using sputtering technology, primarily for fluorescence microscopy.

Usage of Filter: The 735 nm band is used as one specific transmission channel within a "multiband" (e.g., penta-band) interference filter.

Function: It selectively transmits a narrow band of Near-Infrared (NIR) light centered at 735 nm while simultaneously blocking adjacent wavelengths and transmitting other visible bands (like blue, green, and red) on the same substrate.

Result: This achieves high-speed, multi-color imaging without moving parts, allowing researchers to visualize NIR fluorophores (like Cy7) simultaneously with visible markers (like GFP/RFP) on a single image sensor.

Context: This patent details a medical imaging system used during surgery to visualize tissue perfusion and anatomy using fluorescent dyes.

Usage of Filter: The bandpass filter is utilized as an excitation filter placed in front of the illumination source (LED or Laser).

Function: It cleans the light source output, restricting it to a precise 735 nm range to efficiently excite a specific fluorophore (such as a methylene blue derivative or NIR dye) while blocking any "tail" energy that might overlap with the detection range.

Result: This achieves a high Signal-to-Noise Ratio (SNR) in the final image, ensuring that the camera detects only the glowing tissue and not the reflected light from the illuminator.