A New Network Method for the Interreflections in Nonclosed Surfaces

A new network method for describing the interreflections of light fluxes within a nonclosed surfaces is obtained by using the transfer factors which are the sum of the shape modulus of all surfaces seen by a given surface. The transfer factors are always unity in the case of the interreflections within an enclosure, but are not unity in the case of nonenclosure; this means that all of the light fluxes leaving a given surface are not used effectively for the interreflections. It may be explained that the transfer factor is expressed as the ratio of the sum of the fluxes initially intercepted by each surface seen by a given surface to the total fluxes leaving the given surface. When all of the transfer factors are unity, i. e., in the case of the closed surface, it is found that the Kirchhoff's node equations for the light flux transfer among nonclosed surfaces are identical to the equations in the case of the enclosure which were obtained by O'Brien. The luminous emittance distributions after interreflections between two parallel ring disks are obtained by this method, using the luminous analogue computer.