A common desire in designing a lighting fixture is to provide such a fixture such that it will provide a uniform level of illumination across its entire aperture. Various techniques have been used to accomplish this. For example, one such light fixture is shown in commonly-assigned U.S. Pat. 4,791,540. The system of that patent uses specialized film in the aperture in order to ensure that the light will undergo multiple reflections before emerging. In this way the light is evenly distributed throughout the optical cavity providing a uniform intensity output.
Another technique is shown in commonly-assigned copending application Ser. No. 192,212, filed May 10, 1988. According to the technique taught therein, a Fresnel-type reflector is provided wherein some of the Fresnel structures have multiple active faces. Some of these faces are used to direct light out of the light fixture in the intended direction, while others are used to discard excess light in areas close to the light source.
USPTO Backgrounds
USPTO Backgrounds