Patent ID: 8602630

Claim:
A light-emitting device comprising: a plate-shaped light guiding member of which one surface in a thickness direction of the light guiding member is formed as a light reflection and exit surface reflecting light inward and exiting the light and of which both side surfaces facing each other in a direction perpendicular to the thickness direction are each formed as a light-incident surface on which the light is incident; a plurality of light-emitting elements which are disposed on the light-incident surfaces of the light guiding member so as to face each other and spaced in a first direction perpendicular to the thickness direction; and a reflection member which is disposed so as to face an opposite surface of the light reflection and exit surface of the light guiding member and which reflects the light reflected inward from the light reflection and exit surface and passing through the light guiding member and makes the light incident from the opposite surface of the light guiding member, wherein the light reflection and exit surface of the light guiding member has a concave-convex pattern including a plurality of convex portions which are continuously formed in the first direction on the light reflection and exit surface of the light guiding member, extends in a second direction perpendicular to the thickness direction and the first direction, and reflects the light emitted from the light-emitting elements inward, and wherein if L is a distance between the light-emitting elements, t is a thickness of the light guiding member, an incident angle φ of the light on the light reflection and exit surface is an angle between a line segment, which is obtained by projecting a light path from the light-emitting element to the light reflection and exit surface on a surface parallel to the light-incident surface, and a line segment, which extends from a central point of the light-emitting element to the light reflection and exit surface in the thickness direction, θ is a maximum angle range of reflected light when light incident at the incident angle φ is reflected inward from the light reflection and exit surface, and ranges close to and distant from the light-emitting element emitting the light with respect to a line segment extending in the thickness direction in the angle range θ are negative and positive ranges, respectively, a value of the angle range θ decreases as a value of the incident angle φ increases in a range of 0<φ<tan −1 (L/t) and the angle range θ covers both of the positive and negative ranges.