Visual perceiving experiment on color rendering of white leds

摘要

In order to evaluate color rendering properties of white LEDs, visual perceiving experiment on color rendering of two types of white LEDs has been proceeded by comparing with three types of conventional fluorescent lamps of the same correlated color temperature: 5000 K. Reproduced colors of various test samples under both LEDs and fluorescent lamps were compared with those illuminated by the standard illuminant. Illuminance at perceived surface was settled to 500 lx.Test light sources are dichromatic white LEDs, trichromatic white LEDs and three different types of conventional fluorescent lamps. As the reference source, specially designed 5000K fluorescent lamp, spectral radiant power distribution of which approximates CIE supplementary standard illuminant: DH was applied.As test color samples, specially adjusted and prepared 15 sheets of color chart, each spectral reflectance distribution of which approximates the spectral radiance factor of CIE-1974 test color samples specified by CIE 13.3 were tested. Visual perceiving properties were evaluated by 7 point scale.In order to evaluate general color perception by LEDs, various practical color objects were examined under the same color evaluating process mentioned above. Representative color objects tested here were dyed fabrics.Result of visual experiments for above 15 sheets of color chart were compared with calculated values of the Color Rendering Indices by the CIE 13.3 (Ra, R9 to R15). Concerning to the General Color Rendering Index (Ra), a coefficient of correlaton was 0.6476 and there was no clear identified differences between white LEDs and fluorescent lamps. As for evaluation of dyed fabrics, preferable reproduced color could be obtained even under dichromatic white LED illumination.It is concluded that concerning to color rendering properties, present white LEDs, both dichromatic and trichromatic can be applied for general lighting.