Impression of the space under the flat type lighting -comparison between OLED and LED-

Organic electroluminescent lighting (OLED) is expected to become one of the next generation lighting devices. In this research, we investigated the impression of a space illuminated by either flat-type LED lighting panels or OLED panels by changing the area of the illumination. The experiment was conducted with a small box in which miniature furniture was placed. Subjects rated the impression of the room for 20 adjective items in five steps while observing the model of the living room. From the results of the rated values, we found that the space illuminated by the surface-emitting type illumination will increase the impression of “brightness” and “uniformity” as the area of illumination increases. Moreover, OLED lighting was found superior in many items, such as "warm" and "soft". From the results of factor analysis, several factors were extracted, such as “amenity”, “activeness”, and “personality”. INTRODUCTION In recent years, Organic Electro-Luminescence (OLED) lighting has been attracting attention as a next-generation illuminant. This type of lighting has several important features including a wide range of illumination, thickness, and flexibility. The researches dealing with OLED in practical use, however, have just started and it is essential to explore various aspects of OLEDs before it enters the market. One of the biggest differences between OLED and other lighting devices is that OLED is a surface-emitting light source. When installed as a ceiling light, it is possible to place many OLED panels right next to each other to occupy a large area of a ceiling. Compared with conventional point or line light sources such as incandescent and fluorescent lamps, the setting of area light sources can cast shadows of the objects in a completely different way. As a result, OLED may mediate a different impression of the space. The purpose of this research is to find the effects of the relative ratio of the light source to the ceiling on the impression of the space under its illumination. Moreover, a flat-panel type LED lighting panel, which looks similar to an OLED panel, has recently entered the market. In order to find the differences in LED and OLED under a similar way of lighting, we repeated the same experiments for both light sources to find any potential effects of the light source on the impression of a space. PA 17