Topo WSDF-1 Hexachromatic Area Light Source

Overview

The Topo WSDF-1 Hexachromatic Area Light Source is a precision-engineered optical calibration and experimental illumination device designed for controlled, spatially uniform emission across six discrete spectral bands. Unlike broadband or tunable sources, the WSDF-1 integrates six independently addressable LED-based light emitters—each centered on a standardized chromatic coordinate (e.g., approximating CIE 1931 x,y targets for red, green, blue, yellow, cyan, and magenta)—mounted behind a diffusing aperture to generate stable, collimated, Lambertian-like planar illumination. Its primary function is to serve as a traceable, repeatable reference source in photometric and colorimetric metrology workflows, particularly where spatial uniformity, spectral stability, and temporal reproducibility are critical. The device operates on standard 220 V AC mains power and delivers output through a precisely machined 20 mm diameter circular aperture, engineered to minimize edge effects and ensure ±2.5% irradiance uniformity over the central 85% of the emission area under steady-state conditions.

Key Features

• Hexachromatic spectral architecture: Six individually controllable LED channels with peak wavelengths aligned to industry-relevant chromaticity regions (e.g., ~625 nm, ~525 nm, ~465 nm, ~580 nm, ~495 nm, ~570 nm), enabling selective excitation and multi-point color space sampling.
• Uniform area illumination: Engineered diffuser optics and thermal management ensure consistent radiance distribution across the φ20 mm output aperture, supporting ISO/CIE-compliant field-of-view alignment in spectroradiometer and imaging colorimeter setups.
• Built-in current regulation and thermal stabilization: Each channel incorporates constant-current drivers and aluminum-core PCB heat sinking, maintaining luminance drift < ±0.8% over 2-hour continuous operation at ambient 23 ± 2 °C.
• Modular integration capability: Designed as a drop-in accessory for blackbody radiation characterization rigs, colorimetric test benches, and CIE illuminant simulation platforms; includes M36×1 threaded mounting interface and 0–10 V analog dimming inputs per channel.
• CE-compliant electrical safety architecture: Reinforced isolation, overvoltage protection, and EMI filtering conform to EN 61000-6-3 and EN 61000-6-4 standards for laboratory-grade instrumentation environments.

Sample Compatibility & Compliance

The WSDF-1 is compatible with standard optical measurement geometries including d/0°, 0°/d, and 45°/0° configurations used in spectroradiometers (e.g., Konica Minolta CS-2000, Admesy Hera), imaging colorimeters (e.g., Radiant Vision Systems ProMetric I-Series), and integrating sphere-based systems. Its fixed-aperture output enables direct substitution into existing blackbody cavity alignment fixtures without recalibration. While not certified to NIST-traceable calibration standards out-of-box, the unit supports post-installation spectral radiance calibration per CIE Publication 127:2007 and ASTM E308-22 methodologies. It meets general laboratory requirements for GLP-aligned optical testing but does not carry FDA 21 CFR Part 11 compliance—data logging and audit trails must be implemented externally via host instrumentation software.

Software & Data Management

The WSDF-1 operates in open-loop mode and does not include embedded firmware or proprietary control software. Channel intensity is adjusted manually via front-panel potentiometers or externally via 0–10 V analog signals (±1% linearity, 12-bit effective resolution). For automated sequencing—such as timed spectral sweeps or stimulus protocols in vision science experiments—it integrates seamlessly with third-party DAQ systems (e.g., National Instruments USB-6009, Thorlabs K-Cube drivers) and LabVIEW™ or Python-based control scripts using standard voltage-output interfaces. No driver installation or SDK is required; all operational parameters are accessible via hardware-level analog I/O.

Applications

• Colorimetric validation of display measurement systems (LCD, OLED, microLED) against CIE 1931 xy chromaticity targets.
• Radiometric characterization of filter-based multispectral imagers and machine vision sensors under controlled spectral stimuli.
• Educational and research use in undergraduate optics labs for teaching CIE chromaticity diagram mapping, metamerism analysis, and spectral power distribution (SPD) reconstruction.
• Supplementary source in blackbody radiation experiments, enabling comparative spectral energy distribution (SED) analysis across non-thermal emissive sources.
• Reference illumination for camera white-balance algorithm development and ISP pipeline verification under known chromatic conditions.

FAQ

Is the WSDF-1 calibrated upon delivery?
No. Calibration certificates are available as an optional service; users must perform spectral radiance calibration using a NIST-traceable spectroradiometer prior to quantitative measurements.
Can individual channels be pulsed or modulated?
Yes—each channel accepts TTL-compatible square-wave modulation up to 1 kHz (50% duty cycle), provided external current-limiting circuitry is applied to prevent LED thermal runaway.
What is the expected lifetime of the LEDs?
Rated L70 lifetime exceeds 15,000 hours at nominal drive current and ambient ≤25 °C; output degrades gradually and monotonically without abrupt failure modes.
Does the unit support USB or RS-232 communication?
No. Control is strictly analog (0–10 V per channel); digital interfacing requires external DAC modules or programmable power supplies.
Is the aperture size customizable?
Standard aperture is fixed at φ20 mm. Custom apertures (e.g., φ10 mm, φ30 mm) are available under OEM agreement with minimum order quantities and extended lead times.