810nm Bandpass Filter

Context: This patent describes a system for measuring the temperature of a semiconductor wafer while it is being heated (annealed) by powerful lasers, including a CO2 laser and an 810nm diode laser.

Usage of Filter: The bandpass filter is used in the pyrometer's optical path to block the specific 810nm wavelength of the heating laser.

Function: Its function is to prevent the intense 810nm heating light from entering the pyrometer sensor, while allowing the thermal radiation emitted by the hot wafer (typically at a different wavelength, e.g., >1400nm) to pass through.

Result: This achieves accurate, noise-free temperature monitoring of the wafer during the annealing process, ensuring the silicon is heated to the exact specification without the sensor being "blinded" by the heating laser.

Context: This patent details an endoscopic system used to visualize fluorescent dyes (fluorophores) like Indocyanine Green (ICG) inside the body during surgeries.

Usage of Filter: An 810nm bandpass filter is typically used as an excitation filter.

Function: It shapes the light from the illumination source (laser or LED) to ensure that only a precise narrow band of light centered around 810nm (or slightly below, e.g., 780-805nm depending on the specific dye peak) hits the tissue to excite the fluorophores.

Result: This maximizes the fluorescence efficiency of the contrast agent while minimizing background "noise" or bleed-through, resulting in high-contrast images of anatomical structures (like bile ducts) that would otherwise be invisible.

Context: This patent relates to a laser delivery system, likely for medical or dental applications, involving a fiber optic tip and a protective window assembly.

Usage of Filter: The "filter" here is often a transmissive window or coating designed to pass the 810nm therapeutic wavelength with high efficiency.

Function: It transmits the high-power 810nm laser energy to the treatment site while managing thermal loads (heat) and protecting the internal fiber optics from debris or back-splatter.

Result: This ensures precise delivery of the laser energy for tissue ablation or treatment while preventing the optical tip from overheating or failing during the procedure.