Nominalizations as sentential arguments

A temperature-compensated optical system for a scanning device. The optical system includes a first optical element having a positive radius of curvature in a plane and a second optical element having a negative radius of curvature in the plane. Both optical elements focus light energy to nearly the same point within a housing of the scanning device. The focal point is on the side of the second optical element that is opposite to the first optical element. In one embodiment, the optical system can be two separate optical elements and, in another embodiment, the optical system can be an integral piece of material, such as plastic, with the first and second optical elements being surfaces on opposite sides of the integral piece.