630nm Bandpass Filter

Context: This patent describes an automated optical inspection system used in manufacturing (e.g., semiconductor components) to detect defects on surfaces.

Usage of Filter: The bandpass filter (or spectral selection mechanism) is used as part of the illumination and imaging path to isolate specific wavelengths. The patent explicitly mentions using a 630nm (±30nm) red light source for surface inspection, while simultaneously using infrared (1200nm) for internal inspection.

Function: The filter ensures that the camera sensor only captures the specific red light reflected from the component's surface, blocking ambient light or the simultaneous infrared backlight used for the internal inspection.

Result: It achieves a high-contrast image of surface defects (like scratches or misalignments) without interference from the internal structure or other light sources, allowing for simultaneous multi-spectral quality control.

Context: This patent, assigned to Olympus Corp, details an endoscopic system for observing living tissue using fluorescence (autofluorescence) to detect lesions or tumors.

Usage of Filter: The bandpass filter is used as a barrier filter (or absorption filter) in the imaging path. While the system excites tissue with blue/UV light, the filter is designed to selectively pass the resulting red autofluorescence (often centering around or cutting on at 630nm) while blocking the excitation light.

Function: It separates the faint red fluorescence signal emitted by the tissue (which indicates the metabolic state or presence of specific porphyrins) from the intense blue excitation light.

Result: It achieves a clear diagnostic image where abnormal tissue appears distinct from healthy tissue based on its fluorescent glow, enabling early detection of cancers or mucosal abnormalities.

Context: This patent relates to the treatment of skin disorders (like actinic keratosis) using 5-aminolevulinic acid (ALA).

Usage of Filter: The bandpass filter is used as a spectral shaping element for the light source. The therapy requires activation of Protoporphyrin IX, which has a specific absorption peak at 630nm.

Function: The filter narrows the output of a broadband lamp (if a pure laser is not used) to the precise 630nm ±10nm window. This maximizes the photochemical activation of the drug while minimizing unnecessary heat or exposure to UV/IR radiation.

Result: It achieves an effective therapeutic dose that destroys the targeted lesion cells via singlet oxygen production, while sparing the surrounding healthy skin from thermal damage or ineffective radiation.