LCD display with microtextured back reflector and method for making same
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Citation (published version)Greg Blonder. "LCD display with microtextured back reflector and method for making same." U.S. Patent 5,245,454-A.
Applicant has discovered a method for microembossing reflector surfaces with controlled reflecting patterns too small to be resolved by the unaided eye but capable of providing controlled reflection characteristics superior to uncontrolled random deformation. The result is a microtextured reflector of having dispersion characteristics of enhanced uniformity and a display device which can be read over an enhanced range of viewing angles. Specifically, a reflector in accordance with the invention comprises a base plane and a pattern of microelements having maximum lateral dimensions less than 125 micrometers and smooth, continuous mold-formed surfaces arising from the base plane. Such a reflector surface can be made using a master formed by covering a substrate with photoresist, exposing the resist to define a pattern of microelements having maximum lateral dimensions less than about 125 micrometers and heating the substrate to partially melt the resist elements thereby obtaining smooth-surfaced microelements. The master can be used to form an embossing surface or mold, which, in turn, can be used to make a microtextured reflecting surfaces. A preferred reflecting surface is composed of closely packed, smooth-surfaced spherical segments having diameters of twenty-five microns, altitudes of four microns. Advantageously random segments are disposed between successive spherical segments. The preferred reflector possesses reflecting characteristics superior to conventional isotropic reflectors.