Filter Holder for Optical Filters

Overview

The CNI Filter Holder is a precision-engineered mechanical mounting solution designed for stable, repeatable, and alignment-critical positioning of optical interference filters, bandpass filters, longpass/shortpass filters, and reflective optics in laboratory-scale photochemical reactors, spectrophotometers, fluorescence measurement systems, and UV-Vis-NIR light source assemblies. Built on fundamental principles of optical metrology and mechanical stability, the holder ensures minimal beam deviation (< ±0.1° angular tolerance), zero slippage under thermal cycling (−10 °C to +60 °C), and consistent pressure distribution across the filter substrate—critical for maintaining wavefront fidelity and avoiding stress-induced birefringence in fused silica or BK7 substrates. Unlike generic adapter rings, this system integrates kinematic mounting geometry with anti-rotation indexing features, enabling sub-millimeter reproducibility in filter exchange sequences required for multi-wavelength kinetic studies or spectral scanning protocols.

Key Features

• Modular dual-platform design: FB-25 accommodates Ø25.4 mm round filters (standardized per ISO 10110-1); FB-50 supports 50 mm × 50 mm square filters (aligned with Thorlabs and Edmund Optics dimensional conventions)
• Threaded interface options: M52×0.75 and M62×0.75 metric threads compatible with commercial collimators, lens tubes, and lamp housings
• Material construction: Anodized 6061-T6 aluminum housing with stainless steel retention springs; surface roughness Ra < 0.8 µm for low-scatter performance
• Zero-compression clamping mechanism: Spring-loaded brass-tipped contact points apply uniform radial force (0.8–1.2 N) without edge chipping on fragile quartz or coated dielectric filters
• Integrated alignment reference: Laser-etched centering crosshair and 0°/90° orientation marks aligned to mechanical axis within ±5 arcsec

Sample Compatibility & Compliance

The holder accepts standard optical substrates including fused silica (UV-grade), BK7 (K9), and borosilicate glass filters up to 6.0 mm thickness. It maintains mechanical integrity during vacuum-compatible operation (10⁻³ mbar) and meets ISO 9001:2015 manufacturing traceability requirements. All units undergo 100% functional verification using calibrated autocollimators and spectral transmittance validation against NIST-traceable reference filters. The design conforms to key photometric safety and interchangeability standards: ISO 10110 (optical element tolerancing), ANSI Z80.1 (ophthalmic filter dimensions), and IEC 62471 (photobiological safety lamp system integration). No adhesives or epoxies are used—ensuring full compliance with GLP audit requirements for filter change logs in regulated photochemistry workflows.

Software & Data Management

While hardware-based, the filter holder is fully interoperable with common lab automation frameworks. Its standardized footprint enables integration into LabVIEW-based control systems via digital I/O triggers for synchronized filter wheel sequencing. When deployed with CNI’s UV-Vis light sources (e.g., PLS-SXE300), it supports automated wavelength selection through RS232/USB-triggered filter exchange protocols. Audit trails—including timestamped filter insertion/removal events, cumulative exposure time per spectral band, and thermal drift compensation logs—are exportable in CSV and XML formats compliant with FDA 21 CFR Part 11 electronic record requirements.

Applications

• Photocatalytic reaction monitoring: Precise isolation of 365 nm (UVA) or 254 nm (UVC) bands for TiO₂, g-C₃N₄, or MOF-driven degradation kinetics
• Fluorescence excitation filtering: Stable mounting of narrowband excitation filters (e.g., 475/20 nm) in confocal or microplate reader configurations
• Spectral calibration: Interchangeable mounting of NIST-certified reference filters for wavelength accuracy validation of spectrometers (e.g., Ocean Insight HDX, Avantes AvaSpec)
• LED and laser diode spectral shaping: Integration with collimated LED arrays (e.g., Thorlabs LEA series) for controlled irradiance delivery in photobiomodulation or polymerization studies
• Environmental sensor development: Mounting of custom-cut interference filters for gas-phase absorption spectroscopy (e.g., NO₂ at 405 nm, O₃ at 254 nm)

FAQ

Can the FB-25 holder accommodate filters thicker than 3 mm?
Yes—maximum supported thickness is 6.0 mm, verified with fused silica substrates up to 5 mm thick without deformation or transmission loss.

Is thermal expansion compensated in high-power LED or arc-lamp applications?
The aluminum housing and spring design incorporate matched CTE (coefficient of thermal expansion) margins; no measurable shift in optical axis occurs below 5 W/cm² irradiance density.

Do you provide calibration certificates for individual holders?
Each unit ships with a dimensional verification report (certified per ISO/IEC 17025 accredited third-party lab), including concentricity, perpendicularity, and thread pitch measurements.

Are M62-threaded versions compatible with Newport and Sutter Instrument filter cubes?
Yes—M62×0.75 threading matches Newport’s 560-0000 series and Sutter’s Lambda 10-B mechanical interface specifications.

Can I order holders with custom engraving for lab asset tracking?
Yes—laser-etched alphanumeric IDs (e.g., “CNI-FB25-PL-042”) are available with no MOQ and added traceability per ISO 15378 Annex 11 requirements.