Abstract: The present invention features apparatus and a method for controlling luminance emitted from a back light module for a large, tiled, flat-panel, liquid crystal display (LCD). A mechanism is provided for achieving luminance stability of fluorescent lamps, high efficiency and long life through controlling and maintaining lamp tube wall temperatures. Air flow variations are controlled by a microprocessor and a network of electric fans. The lamps may also be dimmed selectively to obtain optimum lamp tube wall temperatures. There is also provided a mechanism for safely preventing overheating of the back light and display due to high ambient temperatures or component failures. Further, the controls can be used in conjunction with ambient light sensing or manual controls to maintain appropriate output light intensity.

Abstract: The present invention features apparatus for uniformly distributing luminance from a back light module for a flat panel, liquid crystal display (LCD). Luminance uniformity, high efficiency and long lamp life are achieved by distributing the lamp cathode thermal energy and maintaining uniform lamp wall temperatures. A heat sink is attached to the fluorescent lamps in the cathode areas, providing cooler operating temperatures at the lamp ends. A thermal sensor is also mounted in the heat sink body. In addition, open louver slots positioned behind the lamps allow for cool air to enter behind each lamp. The size, shape and position of these louvers can be selected so that the lamp temperatures are essentially constant over their entire length.

Abstract: The present invention features a system for uniformly distributing luminance and a high degree of collimation from a back light module for a flat-panel, liquid crystal display (LCD). A constant and uniform luminance output of the back light module is obtained through appropriate selection of lamps, geometry and optical components. An appropriate balance of lamps, lamp spacing, reflective light back plane, and diffuser and collimating optics are chosen to produce a high brightness back light module with very high intensity output over very large surfaces. Variations in intensity over the illuminated area are minimized using light recycling in conjunction with the collimating optics. Optimum geometries are determined for the purpose of maximizing light output at high efficiencies, while minimizing luminance gradients across the display. Finally, a precise collimator eliminates light beyond a defined angle, as required in a tiled, flat-panel LCD.