Quality of finish measurement optical instrument

Abstract

A small battery powered instrument and method for measuring the finish appearance quality of highly reflective surfaces such as the paint on the exterior body panels of automotive vehicles. The instrument is placed on the surface to be measured; ambient light is prevented from entering from the interior space of the instrument by its opaque enclosure and by a seal which contacts the reflective surface. The user looks through a binocular viewing port at a reflection of a test object on the surface. The test object is illuminated by an internal bulb and internal power source which enables the instrument to be used in the field or with any ambient light levels. In the preferred embodiment, the test object is comprised of lines of alphanumeric characters; each line has successively smaller characters and the reflection is viewed at a fixed 20 degree angle to perpendicular to the surface. The measured value of the surface's finish appearance quality is the number of the line that has the smallest characters which are all clearly recognizable to the user. The instrument is comprised of a minimum number of optical components to make this measurement affordable to new markets. The alphanumeric characters provide a greater degree of precision in discerning small differences in finish appearance quality than test objects in the prior art.