Light Rod for Accelerating Algae Growth

Abstract

A light pipe for use in aqueous environments comprising an optical rod capable of total internal reflection, and disposed in the optical path of a light source such as a light emitting diode or other source. The optical rod has frosted and unfrosted portions, such that the light is propagated distally along the rod at the unfrosted portions, but a portion of the light is coupled out of the rod into the aqueous environment at each of the frosted portions. The relative sizes of the frosted portions are arranged so that substantially the same light power is coupled out of the rod at each frosted section, thus facilitating rapid and uniform growth of algae in the aqueous environment.

1 . A light pipe for accelerating algae growth comprising
 a light source for emitting light, and   a rod, capable of total internal reflection, placed in the optical path of the light emitted from the light source so as to receive substantially all of the emitted light, and having alternating frosted and unfrosted portions, whereby the light is propagated down the rod at the unfrosted sections, and a portion of the light is coupled out of the rod at the frosted sections.   
     
     
         2 . The light pipe of  claim 1  wherein the rod has an input face, and further comprising a homogenizer with input and output faces, placed in the optical path of the light and the rod, such that the output face of the homogenizer is contained within the input face of the rod. 
     
     
         3 . The light pipe of  claim 1  wherein the light source is an LED. 
     
     
         4 . The light pipe of  claim 1  wherein the light source is a laser. 
     
     
         5 . The light pipe of  claim 1  wherein the rod has a circular cross-section. 
     
     
         6 . The light pipe of  claim 1  wherein the rod has other than a circular cross-section. 
     
     
         7 . A light pipe for use in aqueous environments comprising
 a light source for emitting light, and   an optical pipe capable of total internal reflection disposed in the optical path of the emitted light, the optical pipe having N segments of substantially equal length, wherein each segment comprises a frosted portion and an unfrosted portion, and the ratio of the length of the frosted portion to length of the unfrosted portion increases in the distal direction of the rod.