PHOTOLUMINESCENT LIGHT EMITTER WITH ENHANCED PHOTOMETRIC BRIGHTNESS CHARACTERISTICS

摘要

A photoluminescent light emitter has higher surface luminance and lumimous exitance characteristics as compared with those of current photoluminescent light emitters. The light emitter may be implemented without the use of refractive elements and has high surface luminance characteristics in substantially all viewing directions. This performance is accomplished by substantially increasing the effective surface area of the photoluminescent material from which the reradiated light is emitted through controlled texturing of the exposed photoluminescent surface. Photoluminescent material with a textured surface emits a portion of light that is incident upon the surface and does not propagate immediately into the environment. Upon reflection by the textured surface, this light is added to the emitted light and thereby increases the measurable luminance of the exposed photoluminescent surface. Certain embodiments take advantage of the self-excitation properties of certain photoluminescent pigments in which the spectrum of the emitted light overlaps the spectrum of the excitation light. Some of the emitted light incident upon the textured surface is absorbed rather than reflected. Of this light, some of its energy excites the photoluminescent pigments rather than being converted to thermal heat energy. This absorbed energy is later reradiated as light within the emission spectrum of the pigments, thereby further increasing the overall luminous exitance of the photoluminescent materials.