| 摘要 |
PROBLEM TO BE SOLVED: To make light rays from a light source incident into a light guide plate without unnecessary loss, and to provide bright emission light without irregularity even at the corners of the light guide plate. SOLUTION: This flat lighting system 1 has the light source 2 and the light guide plate 3. The light guide plate 3 has a front face 4 or a rear face 5 emitting the light from the light source 2, and side face 6 perpendicular to the front face 4 and the rear face 5. In the flat lighting system 1, an isosceles triangle-like protrusion part 8 wherein an angle made by the base to a side connected to the base is nearly equal to a critical angle in a light guide plate material is formed projectingly from one side face part 6. A tip of the protrusion 8 is formed with an incident part 7 cut in an ark shape, and the light source 2 is provided near the incident part 7. |
