| 主权项 |
1. An edge-light type surface light source device, comprising:
a light guide section; and a plurality of light sources each of which emits light via a side surface of the light guide section toward the light guide section, the plurality of light sources being provided on a pair of sides of the light guide section which pair of sides face each other, a longest one of light emitting parts of the respective plurality of light sources having a length shorter than lengths of the respective pair of sides of the light guide section on which the plurality of light sources are provided, the plurality of light sources being each configured to emit light having a first luminance gradient on an edge of a range, to be irradiated with light, which first luminance gradient is smaller than a second luminance gradient of light having a substantially uniform luminance on an entire range to be irradiated with light, wherein L+(N−1)y/√(λ2−1)≧x is satisfied, where (i) λ indicates a refractive index of the light guide section, (ii) x indicates a length of each of the pair of sides of the light guide section, (iii) y indicates a length of a side of the light guide section, the side being neither one of the pair of sides of the light guide section, (iv) L indicates a sum total of the lengths of the respective plurality of light sources which are provided on the pair of sides each having the length x, and (v) N indicates the number of the plurality of light sources which are provided on the pair of sides each having the length x. |
