PROBLEM TO BE SOLVED: To provide a lighting apparatus for an artificial light utilization type plant factory capable of providing light irradiation which is uniform and highly bright as much as possible from a light source over a wide range, being required as the lighting apparatus for the artificial light utilization type plant factory.SOLUTION: A lighting apparatus for an artificial light utilization type plant factory facilitates that, when an optical path of light (emission light L16 from a light source module 16) which proceeds through the interior of a light guide plate 14 is refracted on an upper surface 14a or a lower surface 14b of the light guide plate 14, the optical path of light is refracted to the lower surface 14b direction of the light guide plate 14 by a dot pattern engraved on the upper surface 14a of the light guide plate 14. That is, the optical path of light L16 which proceeds through the interior of the light guide plate 14, when arriving at the upper surface 14a or the lower surface 14b of the light guide plate at an angle of a total reflection angle or less, is not emitted from the light guide plate 14 but is totally reflected into the light guide plate 14. Therein, the optical path of light which proceeds through the interior of the light guide plate 14 is deflected into an angle which exceeds the total reflection angle by the dots 40 which constitute the dot pattern and the emission from the lower surface 14b of the light guide plate 14 is facilitated.COPYRIGHT: (C)2014,JPO&INPIT【課題】人工光利用型植物工場向け照明装置として要求される、光源から広範囲にわたり可能な限り均一かつ高輝度な光照射を実現する。【解決手段】導光板14内を進行する光(光源モジュール16からの出射光L16)の光路が、導光板14の上面14a又は下面14bで屈折される際に、導光板14の上面14aに刻印されたドットパターンによって、導光板14の下面14b方向へと屈折するよう促す。すなわち、導光板14内を進行する光L16の光路は、全反射角度以下の角度で導光板の上面14a又は下面14bに到達すると、導光板14から出射することなく、導光板14内に全反射されることとなる。この際、ドットパターンを構成するドット40によって、導光板14内を進行する光の光路を、全反射角度を超える角度へと偏向し、導光板14の下面14bからの出射を促す。【選択図】図1
