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Proceedings Paper

Experimental measurements of glare in cathode-ray tubes
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Paper Abstract

Multiple light reflections in the emissive structure and electron backscattering processes, in the vacuum of cathode- ray tubes (CRT) are sources of luminance spread and loss of image quality. To perform glare measurements in CRTs, a detector that can record low intensity signals from small dark fields in the presence of a bright surrounding field is required. We have designed and constructed a luminance probe consisting of a cone-shaped nose and an internally baffled barrel that measures light generated in a spot of abut 4 mm diameter. The probe minimizes light scattering from the probe back into the faceplate, and minimizes contributions from bright surrounding regions. In this paper, we report results on the performance of the probe and demonstrate its application for characterizing CRT devices. The probe is shown to be capable of measuring contrast ratios of at least 800 for dark fields with a radius of 2 cm. Measurements on a medical imaging CRTs illustrate how significant veiling glare in the device can result is contrast ratios of about 100 and how the reflection of ambient light can reduce the contrast ratio to below 25.

Paper Details

Date Published: 26 June 1998
PDF: 9 pages
Proc. SPIE 3335, Medical Imaging 1998: Image Display, (26 June 1998); doi: 10.1117/12.312492
Show Author Affiliations
Aldo Badano, Henry Ford Health System and Univ. of Michigan (United States)
Michael J. Flynn, Henry Ford Health System and Univ. of Michigan (United States)

Published in SPIE Proceedings Vol. 3335:
Medical Imaging 1998: Image Display
Yongmin Kim; Seong Ki Mun, Editor(s)

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