TA51 / DA400 / DA20 Autocollimator Series – Precision Angular Metrology Instrument

Overview

The TA51, DA400, and DA20 autocollimators are high-precision optical angular measurement instruments engineered for metrological-grade evaluation of small angular deviations. Based on the principle of autocollimation—where a collimated beam is reflected from a target mirror and re-imaged onto a high-resolution reticle or electronic sensor—these instruments quantify angular displacement by measuring the lateral shift of the returned image. This non-contact, drift-compensated methodology delivers traceable, repeatable angular metrology essential in calibration laboratories, precision machine tool verification, and aerospace component alignment. Each model is optimized for distinct operational envelopes: the TA51 serves as a robust general-purpose unit; the DA400 balances extended range with sub-arcsecond resolution; and the DA20 is designed for ultra-fine angular metrology in controlled environments such as national metrology institutes or semiconductor equipment OEM integration.

Key Features

• Two-axis angular measurement capability (horizontal and vertical planes), enabling simultaneous evaluation of pitch and yaw deviations
• Optical design incorporating high-stability air-spaced doublet collimating lenses and anti-reflection coated optics to minimize chromatic aberration and thermal drift
• Digital readout with real-time display of angular deviation in arcseconds (″), arcminutes (′), or milliradians (mrad), configurable via front-panel interface
• Integrated reference mirror mount compatible with kinematic or vacuum-compatible fixtures for repeatable setup across calibration cycles
• Robust mechanical housing rated to IP52, with temperature-compensated aluminum alloy baseplate minimizing thermal expansion effects during extended measurements
• Compliance with ISO 10360-8 (coordinate measuring machines — part 8: laser trackers) and ISO 230-1 (test code for machine tools — part 1: geometric accuracy) for angular performance validation

Sample Compatibility & Compliance

These autocollimators require a reflective surface—typically a first-surface mirror or optically polished metal reference plane—with minimum reflectivity ≥95% at 532 nm (He–Ne or green LED illumination wavelength). Mirror flatness must be ≤λ/10 over the illuminated aperture to avoid wavefront distortion-induced measurement bias. The TA51 supports standard mirror sizes up to Ø75 mm; DA400 and DA20 accommodate Ø50 mm mirrors with optional custom mounts for interferometric-grade substrates. All models meet CE marking requirements for electromagnetic compatibility (EN 61326-1) and low-voltage directive (2014/35/EU). Calibration certificates are issued per ISO/IEC 17025:2017 by UKAS-accredited laboratories, including uncertainty budgets traceable to NPL (National Physical Laboratory, UK).

Software & Data Management

Optional PC-based control software provides automated data logging, statistical process control (SPC) charting, and multi-point angular mapping. The software supports export to CSV, XML, and MATLAB .mat formats, and includes built-in routines for straightness, flatness, and squareness evaluation per ISO 230-6. Audit trails record operator ID, timestamp, environmental conditions (temperature/humidity input), and instrument configuration changes—fully compliant with FDA 21 CFR Part 11 for regulated manufacturing environments. Raw image frames from the detector array can be archived for retrospective analysis, supporting GLP/GMP documentation requirements.

Applications

• Calibration of rotary tables and precision goniometers against national angular standards
• Verification of linear axis straightness and angular errors (pitch/yaw/roll) in CNC machine tools per ISO 230-2
• Measurement of perpendicularity between orthogonal axes in multi-axis coordinate measuring machines (CMMs)
• Alignment of optical benches, laser cavities, and synchrotron beamline components
• Flatness assessment of granite surface plates and optical reference flats using grid-based autocollimator scanning
• Dynamic angular monitoring during thermal soak tests of structural assemblies using synchronized frame capture

FAQ

What is the maximum working distance for each model?

The TA51 is specified for optimal performance at 9 m; DA400 and DA20 are calibrated for 5 m baseline distances. Extended-range operation beyond these distances is possible but requires recalibration and introduces additional uncertainty due to beam divergence and atmospheric turbulence.
Can these autocollimators measure dynamic angular motion?

Yes—when paired with the optional high-speed camera module (up to 200 Hz frame rate), real-time angular tracking is supported. However, the DA20’s ultra-high resolution mode reduces effective sampling rate to ~10 Hz to maintain signal-to-noise ratio.
Is mirror alignment critical before measurement?

Yes. Initial coarse alignment (within ±5°) is required to ensure the return beam enters the instrument aperture. Built-in alignment aids—including crosshair reticles and auxiliary LED indicators—assist rapid setup without external alignment tools.
Do these instruments require periodic recalibration?

Per ISO/IEC 17025 and internal quality protocols, annual recalibration is recommended. Instruments used in accredited calibration labs must undergo verification before each major measurement campaign, with full calibration every 12 months or after mechanical shock or environmental exposure exceeding specification limits.
Are accessories such as mounting brackets and calibration mirrors included?

Standard delivery includes a rigid tripod mount, leveling base, and one certified reference mirror (λ/20 flatness). Optional accessories include motorized mirror stages, vacuum-compatible mounts, and NIST-traceable angular calibration sets covering ±1000″ range.