To solve problems of high maintenance cost due to a short inspection and maintenance time span, and high electric power cost due to high power consumption when a lighting device is used as a backlight for an illuminated sign or the like.
The lighting device includes a base part 1, an approximately box shaped reflecting structure 7 arranged on the base part and having a bottom surface part 8 and side surface parts 9 raised from respective side parts 8a of the bottom surface part in an approximately same direction, and light emitting elements 11 arranged on respective corner parts or respective side parts of the reflecting structure. A center part of the bottom surface part of the reflecting structure is formed in a mountain-like shape 10 in an approximately whole circumferential direction, and shapes of inclined surfaces of the mountain-like part 10a opposite to the respective corner parts or respective side parts are approximately equal.
YAMAMOTO MASAHIKO
KOJIMA MASAYUKI
