Patent ID: 9405110
Filing Date: 2016-08-02
CPC Classification: F21Y,G02B

Claim Text:
1. A surface light source device comprising: a substrate; a plurality of light emitting devices, each of which includes a light emitting element, and a light flux controlling member that controls a distribution of emission light from the light emitting element, the light emitting devices being disposed at constant intervals on the substrate; and a light diffusion plate disposed substantially parallel to the substrate over the plurality of light emitting devices, the light diffusion plate being configured to transmit light from each light emitting device while diffusing the light, wherein in an angular range from a direction along an optical axis of the light emitting device to a direction of emission of light with the highest luminous intensity from the light emitting device, a luminous intensity of light from the light emitting device is gradually increased as an angle of the light relative to the optical axis becomes larger, and the surface light source device is constructed such that following Equations 1, 2 and 3 are satisfied: where P is a center-to-center distance between the light emitting devices adjacent to each other, H is an interval between an upper surface of the substrate and a lower surface of the light diffusion plate, L is a distance from an intersection point of the optical axis and the lower surface of the light diffusion plate to a point where the light with the highest luminous intensity reaches the lower surface of the light diffusion plate, I