Patent ID: 7014349

Claim:
A surface light source device comprising: a light conductor plate for spreading an introduced light on nearly an entirety of a light emitting surface and emitting the introduced light from the light emitting surface; a light source smaller in size as compared to a light incident surface of the light conductor plate; and luminous flux shaping means for spreading a light emitted from the light source to nearly the entirety of the light incident surface and emitting the light, wherein at least 50% of the incident light on the light conductor plate is included in an area defined by angles of 26 degrees as viewed from a direction perpendicular to the light emitting surface of the light conductor plate, and wherein at least two-thirds of a total light emitted from the luminous flux shaping means is emitted to an area defined by angles of up to 40 degrees from a lengthwise direction of a light emitting surface of the luminous flux shaping means as viewed from a direction perpendicular to the light emitting surface of the light conductor plate, wherein the luminous flux shaping means comprises, at a light emitting surface side, means to deflect the light emitted from the luminous flux shaping means to a direction perpendicular to a light emitting surface of the luminous flux shaping means.