Abstract: According to one embodiment, a method is disclosed for evaluating discomfort glare. The method can include obtaining average luminance information relating to an average luminance La of a luminous surface of a luminaire, luminance uniformity ratio information relating to a luminance uniformity ratio U of the luminous surface, luminous surface size information relating to a size ? of the luminous surface, and background luminance information relating to a background luminance Lb of the luminaire. The method can include calculating an evaluation parameter value based on the La, the U, the ?, and the Lb obtained in the obtaining. The evaluation parameter value is a value of a product of a value based on the La, a value based on the U, and a value based on the ? divided by a value based on the Lb.

Abstract: According to an embodiment, a luminaire includes a plurality of light source units having mutually different characteristics; and a plurality of diffusing units configured to diffuse light emitted from the light source units and have mutually different characteristics.

Abstract: In a luminaire, a diffusing unit diffuses the light, which has been emitted from a light source unit, according to light transmissibility. A position information obtaining unit obtains position information which at least indicates the position of a person. A luminance obtaining unit obtains the luminance of a luminous part at the position specified in the position information. A calculating unit calculates, according to the light transmissibility and the luminance of the luminous part, a luminance uniformity ratio which indicates the uniformity in the luminance distribution in the luminous part at the position specified in the position information. According to the luminance and the luminance uniformity ratio, a control unit varies the light transmissibility and varies the light output of the light source unit.

Abstract: According to one embodiment, a method is disclosed for evaluating discomfort glare. The method can include obtaining average luminance information relating to an average luminance La of a luminous surface of a luminaire, luminance uniformity ratio information relating to a luminance uniformity ratio U of the luminous surface, luminous surface size information relating to a size ? of the luminous surface, and background luminance information relating to a background luminance Lb of the luminaire. The method can include calculating an evaluation parameter value based on the La, the U, the ?, and the Lb obtained in the obtaining. The evaluation parameter value is a value of a product of a value based on the La, a value based on the U, and a value based on the ? divided by a value based on the Lb.