A vacuum truck solids handling apparatus includes a truck having an internal combustion engine and a truck frame. The reflection electrode does not cover the wiring layer therewith, and the compensation layer has almost the same height as a height of the reflection electrode, the height being measured from a surface of the first substrate. A leaf spring is connected to the lower portion of the knuckles at pivotal connections and serves as the lower control arms. The light engine provides light suitable for applications in microscopy, endoscopy, andor bioanalytical instrumentation.