Labsphere PT-038-PLS Portable Integrating Sphere Standard Light Source

Overview

The Labsphere PT-038-PLS Portable Integrating Sphere Standard Light Source is an engineered optical reference instrument designed to deliver spatially uniform, spectrally stable, and radiometrically traceable luminance output for field and laboratory calibration applications. Based on a precision-machined, BaSO₄-coated integrating sphere geometry (38 cm diameter), the system operates on the principle of multiple diffuse reflections to homogenize radiant flux from a stabilized tungsten-halogen lamp, producing Lambertian emission across its exit port. Unlike fixed-benchtop standards, the PT-038-PLS integrates thermal management, electronic current regulation, and mechanical port shielding to maintain photometric stability under variable ambient conditions—enabling direct on-site verification of luminance meters, imaging photometers, and spectral radiometers without requiring controlled lab environments.

Key Features

• High spatial uniformity (≤ ±0.5% deviation across central 80% of exit port), validated per CIE Publication 127 and ISO/CIE 19476:2014 guidelines for luminance standard characterization
• Wide dynamic luminance range (0.1–10,000 cd/m²) achieved through calibrated neutral-density filter wheel and precision lamp current control, supporting both low-light display metrology and high-brightness automotive HUD validation
• Thermal stabilization architecture with closed-loop temperature monitoring and active lamp power compensation ensures ≤ ±0.2% short-term stability over 30 minutes—critical for GLP-compliant calibration workflows
• Compact, ruggedized aluminum housing with integrated carrying handle and optional rechargeable Li-ion battery pack (up to 4 hours continuous operation)
• NIST-traceable calibration certificate supplied with each unit, covering luminance, chromaticity (CIE 1931 x,y), and spectral radiance at multiple output levels; certificate includes uncertainty budgets per ISO/IEC 17025:2017 requirements
• Modular port configuration supporting interchangeable exit apertures (25 mm, 50 mm, 75 mm) and optional fiber-coupled or collimated output adapters

Sample Compatibility & Compliance

The PT-038-PLS is compatible with all luminance-measuring instruments featuring entrance optics aligned to CIE standard observer functions (photopic V(λ), scotopic V′(λ), or custom spectral responsivity curves). It supports calibration of handheld luminance meters (e.g., Konica Minolta LS-150, Topcon BM-7A), imaging colorimeters (e.g., Radiant Imaging ProMetric series), CCD/CMOS-based radiometric cameras, and OEM sensor modules used in display manufacturing QA lines. The device conforms to international standards including ASTM E308-23 (computing tristimulus values), ISO 9241-305 (display optical measurement), and IEC 62368-1 Annex D (luminance safety testing). All calibrations are performed in accordance with ISO/IEC 17025-accredited procedures, and raw spectral data (380–1000 nm at 1 nm intervals) is provided in ASCII format for third-party software integration.

Software & Data Management

While the PT-038-PLS operates as a stand-alone hardware standard, Labsphere provides optional LabSphere Control Suite v3.2—a Windows-based application enabling remote luminance level setting, real-time stability logging, and automated calibration report generation compliant with FDA 21 CFR Part 11 (electronic records/signatures) and EU Annex 11 requirements. Audit trails record operator ID, timestamp, output level, ambient temperature/humidity, and calibration certificate metadata. Export formats include CSV, PDF/A-2b, and XML for LIMS integration. No proprietary drivers or dongles required; USB-C and Bluetooth 5.0 interfaces support secure, low-latency communication.

Applications

• On-site calibration and verification of luminance meters prior to display brightness audits (OLED, microLED, LCD panels)
• Reference source for ISO/IEC 17025-accredited calibration laboratories performing scope expansions in photometry and radiometry
• Validation of image sensor linearity, dynamic range, and gamma response in automotive ADAS camera systems
• Chromaticity and luminance drift assessment during accelerated aging tests of backlight units and emissive signage
• Primary transfer standard for national metrology institutes conducting inter-laboratory comparisons under CCPR Key Comparison protocols
• Teaching tool in university optics labs for demonstrating integrating sphere theory, photometric units, and uncertainty propagation in radiometric measurements

FAQ

Is the PT-038-PLS suitable for calibrating spectroradiometers?
Yes—the system includes full spectral radiance data (380–1000 nm) with NIST-traceable uncertainty values, enabling spectral responsivity correction and absolute irradiance calibration.
Can the unit be operated continuously for extended periods?
Continuous operation is supported for up to 8 hours with external AC power; thermal derating begins after 4 hours on internal battery to preserve lamp lifetime and stability.
Does the calibration certificate cover both luminance and chromaticity?
Yes—certificates report luminance (cd/m²), CIE 1931 chromaticity coordinates (x, y), CCT (K), and dominant wavelength at three intensity levels, with expanded uncertainties reported at k=2.
Is firmware upgrade capability available?
Firmware updates are delivered via signed .hex files through Labsphere’s secure customer portal; no field service visit required.
What maintenance is required to sustain calibration validity?
Annual recalibration is recommended; users must retain original certificate and log lamp operating hours—Labsphere provides lamp replacement kits with pre-aligned filament positioning and updated calibration coefficients.