We are developing a new standard for total spectral radiant flux calibration. The standard is useful for photometric evaluation of light emitting diode (LED) and solid-state lighting (SSL).

LED and SSL show large potential to promote new industries in the future and to reduce the energy consumption of future lighting. However, photometric evaluation of LED or SSL is difficult and it is feared that unreliable evaluations of LED or SSL emerging in the market threaten consumer confidence leading to a delay in market acceptance of LED or SSL.

The difficulty arises from the unique spectral distributions of LED and SSL. The spectral distributions of LED and SSL are quite different from those of the traditional light sources, and the variety of the spectral distributions is much wider than that of the traditional light sources.

The total luminous flux standard, which is widely used for photometric evaluation of the traditional light sources, is not appropriate to LED or SSL evaluation. The total spectral radiant flux standard is necessary for reliable photometric evaluation of LED and SSL.