Patent ID: 7369221
Filing Date: 2008-05-06
Classification: G01N

Abstract:
1. A portable refractometer for measuring an index of refraction of a substance, comprising: a lens barrel having a lens barrel axis; a prism secured to one end of the lens barrel, said prism having an entry face that provides a boundary surface between the prism and a substance to be measured; a tube shaped optical chassis inside the lens barrel, rotatably supported about a predetermined rotational axis perpendicular to the lens barrel axis; an objective lens arranged in the optical chassis, positioned in relation to the optical chassis; an optical scale arranged inside the optical chassis, at a focal point of the objective lens; and a mover that moves the objective lens relative to the optical scale in response to changes in temperature by turning the optical chassis about the rotational axis, the mover comprising a thermally expansive part which is housed in a case which is inserted in an opening in the lens barrel.