| 摘要 |
PROBLEM TO BE SOLVED: To provide a lighting unit excellent in energy conservation and routing of wiring, capable of lighting a work area on a desk as well as a work space where there is a worker, and to provide a desk system with illumination using the lighting unit.SOLUTION: Luminous flux emitted from LEDs 2 is guided while it is totally reflected between a first primary surface 11 and a second primary surface 12, and luminous flux reflected and diffused with a light path deflection means 15 and deviated from a total reflection angle can illuminate a designated work area via a first diffusion plate 5 by being emitted from the first primary surface 11 as first illumination light. On the other hand, luminous flux deviated from the total reflection angle among the light incident to the second primary surface 12 transmits the second primary surface 12, and then, is given directivity while passing through a prism sheet 6, and further, is emitted in nearly a vertical direction as second illumination light through a second diffusion plate 7. Therefore, the luminous flux can illuminate a ceiling or the like in the room where the lighting unit U is arranged, whereby, the lighting unit U with high efficiency can be attained as a whole. |
