MiXran Meg1128 Focal Length Measurement Instrument for Objective Lens Assemblies

Overview

The MiXran Meg1128 Focal Length Measurement Instrument is a precision optical metrology system engineered for quantitative verification of effective focal length (EFL), back focal length (BFL), and principal plane positions of objective lens assemblies used in high-performance imaging, metrology, and laser systems. It operates on the principle of autocollimation combined with calibrated translation-stage displacement measurement and collimated beam analysis—enabling non-contact, sub-millimeter-level repeatability in focal characterization. Unlike empirical alignment methods, the Meg1128 integrates a stabilized He–Ne laser source (632.8 nm), motorized linear stage with ±0.5 µm positional resolution, and a high-dynamic-range CMOS detector array to capture angular deviation of retroreflected beams. This architecture ensures traceable measurements compliant with ISO 10110-2 (optical element surface form tolerances) and supports calibration against NIST-traceable reference standards. The instrument is designed for integration into optical assembly lines, R&D laboratories, and quality assurance workflows where objective lens performance must be validated prior to integration into end-systems such as machine vision cameras, semiconductor inspection tools, or adaptive optics platforms.

Key Features

• Autocollimation-based focal length measurement with <0.1% relative uncertainty for lenses ranging from 50 mm to 2000 mm EFL
• Motorized precision translation stage (travel range: 0–300 mm; repeatability: ±0.5 µm) synchronized with real-time beam centroid tracking
• Dual-mode operation: supports both positive and negative objective configurations via configurable reference mirror positioning
• Integrated 632.8 nm He–Ne laser with TEM₀₀ mode, power stability <±0.3% over 8 hours
• Optical path optimized for minimal wavefront distortion—MgF₂-coated fused silica beam splitters and kinematically mounted mirrors
• Modular mounting interface compatible with standard optical breadboards (M6 and 1/4″-20 threaded holes)
• Thermal drift compensation algorithm embedded in firmware, reducing ambient temperature sensitivity to <0.02 mm/°C over 15–30°C range

Sample Compatibility & Compliance

The Meg1128 accommodates objective lens assemblies with clear apertures up to Ø38 mm and mechanical lengths ≤120 mm. It supports both cemented doublets (e.g., GOBJ-050-38-P50 series) and single-element objectives (e.g., GOBJ-600-38-P600), including air-spaced and meniscus-corrected variants. Mounting is facilitated via adjustable kinematic lens holders with radial centering accuracy better than ±2.5 µm. All measurement protocols adhere to ISO 9001:2015 quality management requirements. Data integrity meets GLP-compliant documentation standards, with audit-ready timestamped logs, operator ID tagging, and raw image capture retention. While not FDA-regulated as a medical device, its measurement traceability aligns with ISO/IEC 17025 calibration laboratory practices when operated with certified reference lenses.

Software & Data Management

The Meg1128 is controlled via MiXran OptiCal v3.2 software (Windows 10/11 64-bit), providing guided measurement workflows, real-time beam profile visualization, and automated EFL/BFL calculation per ISO 10110-5 Annex B. Software features include batch reporting (PDF/CSV export), statistical process control (SPC) charting for production lots, and user-defined pass/fail thresholds based on tolerance bands. Audit trails record all parameter changes, measurement initiations, and calibration events—including digital signatures for QA sign-off. Data files are encrypted using AES-256 and support optional integration with enterprise LIMS via RESTful API (JSON payload). Software validation documentation (IQ/OQ protocols) is available upon request for regulated environments requiring 21 CFR Part 11 compliance.

Applications

• Final acceptance testing of custom objective lens assemblies prior to shipment
• In-process verification during multi-element optical alignment in cleanroom assembly
• Root-cause analysis of focus shift in thermal cycling or mechanical shock tests
• Calibration transfer between metrology labs using common reference objectives
• Verification of lens prescription fidelity after coating or environmental exposure
• Supporting DOE (Design of Experiments) for optical system optimization in academic and industrial R&D

FAQ

What focal length range does the Meg1128 support?
The instrument is validated for objective assemblies with effective focal lengths from 50 mm to 2000 mm, covering both positive and negative configurations.
Is the Meg1128 suitable for measuring aspheric or freeform objectives?
It is optimized for rotationally symmetric objectives; aspheric elements require additional wavefront analysis and are outside the standard scope of Meg1128 measurement capability.
Does the system include NIST-traceable calibration certificates?
Yes—each unit ships with a factory calibration certificate referencing NIST SRM 1920a (fused silica etalon) and includes annual recalibration service options.
Can the Meg1128 integrate with existing lab automation systems?
Yes, via Ethernet-connected remote command interface (SCPI-compatible) and programmable I/O triggers for synchronization with motion controllers or PLCs.
What maintenance is required for long-term measurement stability?
Annual optical alignment verification and laser power calibration are recommended; no consumables or routine part replacement is specified under normal operating conditions.