GS-391 VAAS Reflectance Tester
The Gamma Scientific GS-391 Variable Aperture Annulus Sphere Reflectance Tester automates spectral reflectance measurement for advanced displays and optical surfaces. Designed to separate and quantify specular reflection, haze, and Lambertian reflectance, the GS-391 provides a faster, more automated alternative to traditional BRDF-based methods.
Using a variable aperture annulus light source, precision detection optics, and automated robotic positioning, the GS-391 enables manufacturers and researchers to evaluate how display surfaces perform under real-world lighting conditions—supporting the development of higher-contrast, lower-glare, and more readable displays.
Key Application Areas:
Consumer Electronics: Smartphones, tablets, laptops, and TVs require consistent readability in bright outdoor environments and dim interiors.
Automotive Displays: In-vehicle infotainment, HUDs, and instrument clusters must remain visible in harsh lighting such as sunlight, tunnels, and night driving.
Augmented Reality (AR) & Wearables: AR headsets, helmet visors, and heads-up displays blend digital content with physical environments.
Aerospace & Defense: Cockpit displays, tactical field equipment, and control interfaces require uncompromised readability under extreme lighting conditions.
Medical Devices: Surgical monitors, diagnostic screens, and wearable health technologies must deliver color-accurate, high-contrast visuals in diverse lighting environments, including high-glare ORs and patient settings.
Industrial & Outdoor Systems: Kiosks, point-of-sale systems, and digital signage often operate in high-glare environments such as direct sunlight or warehouse lighting. These applications demand coatings with exceptional anti-reflective and contrast-enhancing properties.
Retail & Showroom Displays: Transparent LCDs used in smart showcases or product displays must balance digital content visibility with the clarity of physical products under controlled but complex lighting
At the Core of the System
The GS-391 VAAS Reflectance Tester automates the measurement of display and surface reflectance by separating reflected light into three key components: specular reflection, haze, and Lambertian reflectance. This distinction is essential because these components often overlap in the specular direction, making it difficult to understand how each one contributes to glare, contrast loss, and perceived display quality.
Using a Variable Aperture Annulus Sphere light source with a central blocking aperture, the GS-391 selectively blocks the specular beam while measuring the remaining reflected light. A spectrometer with a 0.1° measurement field of view captures reflectivity data wavelength by wavelength, while automated positioning enables precise, repeatable measurements across the sample.
By combining measurements taken in the specular direction, adjacent to the blocked specular beam, and 45° from specular, the GS-391 individually quantifies specular, haze, and Lambertian reflectance in a computer-controlled sequence. This makes it well suited for evaluating anti-reflective coatings, cover glass, touch panels, transparent displays, and other optical surfaces used in consumer electronics, automotive, aerospace, medical, and outdoor display applications.
