Serpentine fluorescent lamp with shaped corners providing uniform backlight illumination for displays

摘要

A bent fluorescent lamp for backlighting a display providing uniform illumination. A fluorescent lamp (210; 310)is made from a tubular glass envelope (212; 312) having right angles formed therein with shaped corners (240, 242; 340, 342). The right angles provide improved illumination of a plane surface for backlighting a liquid crystal display (237; 337). The right angles and shaped corners eliminate dark regions in the illuminated surface. A right-angled bend is also formed at the ends of the fluorescent lamp. An electrode (220; 230) is positioned sufficiently far from a central portion (223; 323) of the lamp so that any dark spaces in the gas discharge of the fluorescent lamp (210; 310), such as the Faraday dark space associated with a cathode of a lamp are not formed within the central portion (223; 323). As a result, the central portion of the fluorescent lamp has a uniform brightness or intensity providing improved illumination for backlighting a liquid crystal display (237; 337). The resulting more uniform illumination with less dark regions results in a more legible display. A method of forming a right-angled bend with a shaped corner in a glass tube is also disclosed.