Patent ID: 8928957
Filing Date: 2015-01-06
Classification: H04N

Abstract:
1. A light guide comprising: a first light guide part that guides light beams coming from a light source from an incident part to a constricted part, in a cross section perpendicular to a direction of arrangement of the light source, which is arranged one dimensionally; and a second light guide part that is integrated with the first light guide part and bends the optical path of light beams coming from the incident part and passing through the constricted part in the cross section perpendicular to the direction of arrangement of the light source to guide the light beams to a light exit part having a condensing function through which the light beams exit, wherein the first light guide part has a first side part that totally reflects light beams traveling from the incident part in a first direction and a second side part that totally reflects light beams traveling from the incident part in a second direction in the cross section perpendicular to the direction of arrangement of the light source to deliver light beams traveling from the incident part and totally reflected by at least one of the first side part and the second side part and light beams traveling from the incident part directly without being reflected by the first side part or the second side part to the constricted part in a superposed state, and the second light guide part has a reflection condensing part that has a condensing function in the cross section perpendicular to the direction of arrangement of the light source, is located at a predetermined distance from the constricted part, and totally reflects light beams further diverging after passing through the constricted part, a third side part that runs from the constricted part more outward than an imaginary surface as an extension of the first side part beyond the constricted part to connect the first side part to the light exit part in such a way that light beams traveling from the constricted part toward the reflection condensing part are not restricted, and a fourth side part that runs from the constricted part more outward than an imaginary surface as an extension of the second side part beyond the constricted part to connect the second side part to the reflection condensing part in such a way that light beams traveling from the constricted part toward the reflection condensing part are not restricted and that the reflection condensing part is enlarged.