Abstract: A refrigerator door for a refrigerated display case includes a glass unit having first and second spaced apart glass panels where the first panel has a forward facing surface and the second panel has a rearward facing surface. A spacer element extends between the first and second glass panels. A door rail element includes an external perimeter wall extending from a point adjacent the edge of the first glass panel to a point adjacent the second glass panel. The door rail element also includes a portion which extends within the space between the first and second spaced apart glass panels and a portion which extends externally of the spaced apart glass panels to the perimeter wall. The door rail element further includes a rear wall portion extending inwardly toward the center of the door from the perimeter wall and over a portion of the rearward facing surface of the second glass panel. In one aspect, one or more of the door rail elements may be formed from a composite, for example, resin and glass fibers.

Abstract: A display case lighting system having a lens positioned inside a display case adjacent a light source inside the case for directing light across a viewing plane within the case and reducing contrasting illumination of items displayed within the viewing plane.

Abstract: A ballast circuit is provided having an input, an output for coupling to an electric discharge lamp and an oscillation circuit for illuminating the lamp. A circuit may be included for sensing when current from the isolation circuit exceeds acceptable levels, at which point, the ballast circuit may be shut down, limited or otherwise reducing the possibility of ballast failure. In one form of the invention, a current excursion sensor circuit is coupled between the isolation circuit and the output circuit for sensing when the current from the isolation circuit exceeds a given value. Preferably, the ballast circuit is shut down and maintained inactive until such time as any current excursion has a chance to decay away, ballast components have an opportunity to cool off or otherwise return to normal condition or until such other condition has occurred. Preferably, the ballast is shut down upon a current or voltage excursion of such a magnitude at or before components may overheat or begin to fail.

Abstract: A ballast is disclosed which can operate at an effective level of output with a number of different input voltage levels. A ballast is also disclosed that uses a ceramic as a heat sink for switching transistors. A ballast is further disclosed which uses a start signal for a power factor circuit to boost voltage after the load for the ballast has already had a current applied to it. Furthermore, a ballast is disclosed which has a transformer having a permeability which varies somewhat inversely with temperature over a given temperature range.

Abstract: A refrigerating door construction is disclosed which includes door rail elements form one or more spacer elements between adjacent panels so that separate, discrete spacer bars may be eliminated.