Optical Filter Surface Quality Guide
Importance of Optical Filters
Optical filters are essential for isolating signal light and blocking interference in applications from aerospace to smartphone cameras. Their surface quality directly impacts performance, ensuring accurate imaging and signal detection.
Spectral Performance
Spectral characteristics are critical for optical filters. For example, IR cut-off filters used in digital cameras transmit visible light (400–700 nm) with high efficiency while blocking near-infrared light (700–1100 nm) to ensure true color reproduction.
Surface Figure
Surface figure refers to the overall and local shape of a filter’s surface. Global surface figure defines the filter’s general shape, while local surface irregularities, visible under high magnification, can cause image distortion, especially in imaging applications like microscopy.
Surface Quality
Surface quality, measured by scratches and digs, affects image clarity. Filters placed near image sensors require high surface quality (e.g., 40-20 scratch-dig) to avoid defects impacting sharpness in applications like machine vision.
Surface Roughness
Surface roughness influences light scattering, critical for filters requiring high optical density (e.g., OD5, <0.001% transmittance). In fluorescence systems, fluorescence optical filters demand low roughness to minimize scattering and isolate weak signals effectively.
Imaging vs. Energy Filters
- Imaging Filters: Require precise spectral performance, excellent surface figure, and high surface quality for clear, distortion-free images, such as in cameras or microscopes.
- Energy Filters: Prioritize spectral performance and low roughness for deep blocking (OD5+), as in fluorescence detection, where signal strength matters more than image shape.
Why Choose Our Filters?
OptoStokes offers:
- Precision Optical Filters: High-transmittance IR cut-off filters and fluorescence filters with minimal surface defects.
- Custom and Stock Solutions: Tailored designs for UV, VIS, NIR, and IR applications.
- Global Standards: Quality matching international benchmarks at competitive prices.
