Cut-off Line of Passing Beam-Theory and Practice

摘要

Important part of headlights passing beam image is the "cut-off line".It serve for adjustment of passing beam during type approval and during exploitation aiming.Correct aiming should lead to appropriate road illumination and protect against excessive glare.Cut-off line from it nature is a part separating bright and dark area in the passing beam.Practical function is the visual aiming of headlights in laboratories,in vehicles factories,in services and during technical periodical inspection.Cut-off line was firstly defined over 50 years ago.To guarantee good road visibility and glare protection aiming should have higher precision than present real cut-off shape tollerances.Definition of cut-off line,their performance,changes during years and connection with progress of headlamps design are analyzed.Examples of real cut-off lines,relations with significant beam pattern characteristics and possible aiming results are shown.Perspectives for future cut-off line use,or other means are described.