Abstract: A device and method for uniformly illuminating bar codes and two dimensional symbologies. An illumination source is mounted within the device to flood an area congruent with the field of view of the imaging optics with light to be reflected off of a code symbol. The imaging optics collects the reflected illumination received back through the window and images the same on a detector focal plane. An array of solid state light-emitting diodes are disposed adjacent to the imaging optics and a diffuser is placed between the emitters and the device window for illumination source. The emitters and diffusers are spatially arranged so as to cause homogenous distribution of light energy beyond the window and congruent with the field of view of the imaging optics.

Abstract: A window is transparent to infrared and/or visible radiation, and is shielded against electromagnetic radiation. The window includes a substrate made of a material transparent to the selected wavelength band of radiation, and a multilayer grid pattern overlying the substrate. The grid pattern comprises a first layer of an electrically conductive material adjacent to the substrate, and a second layer of a magnetically permeable material overlying the first layer. Preferably, there is a third layer of an electrically conductive material overlying the second layer.

Abstract: A window includes a first layer of a dielectric first material that transmits radiation in the visible or the infrared, and a second layer positioned adjacent to the first layer. The window is positioned so that the radiation is incident upon the first layer. The second layer is formed of a dielectric or semiconductor second material that transmits radiation in the same wavelength range as the first material. A first electrical conductor lies between the first layer and the second layer. A second electrical conductor lies on at least one of an exterior surface of the first layer remote from the second layer and an interior surface of the second layer remote from the first layer. Where the first and second materials are selected to transmit in the infrared, the first and second electrical conductors are grids. Where the first and second materials are selected to transmit light in the visible, the first and second electrical conductors are continuous layers.

Abstract: A method and apparatus for supplying gypsum slurry of predetermined concentration to a follow-on utilization device, such as an irrigation network. Slurry of a first higher concentration is prepared in a vessel using a vertically arranged mixer with power and drive components mounted outside the tank and a mixer shaft bearing an impeller and a propeller positioned inside the tank for immersion in the slurry ingredients. Rotation of the impeller and propeller causes the slurry ingredients to flow downwardly in the central region of the vessel, outwardly near the bottom towards the inner wall surfaces, upwardly of the inner wall surfaces towards the top and inwardly to the central region in a cyclic fashion to produce a uniform slurry. The slurry is withdrawn through an outlet in one of the tank walls and mixed with externally supplied water in a mixing chamber to dilute the slurry to a desired useable concentration.