| 摘要 |
<p>A lighting device of the invention is a lighting device, including: a light source device having a light-emitting tube and an ellipsoidal reflector; a concave lens having a light-incident surface formed from a hyperboloid of revolution to make the illuminating luminous flux from the light source device almost parallel; a first lens array; and a second lens array, which is characterized in that a concave surface is present between the light-incident surface of the concave lens and the first lens array on a surface where the plural small lenses are formed, and the concave surface is furnished with a function of causing, together with the light-incident surface of the concave lens, an illuminating luminous flux having passed through the light-incident surface of the concave lens to travel along an optical path heading to an outer side than an optical path parallel to an optical axis of the light source device, while causing the illuminating luminous flux to pass through the small lenses that correspond to each other in the first lens array and the second lens array. It is thus possible to reduce losses in quantity of light, which can in turn improve efficiency of utilization of illuminating luminous fluxes.</p> |
