LIGHT SOURCE DEVICE AND LIGHT POLARIZATION ELEMENT USED FOR IT

摘要

PROBLEM TO BE SOLVED: To provide a light source device with wide distribution angle range of output light intensity, with reduced distribution unevenness within the range and with which picture quality of a display unit can easily be improved. SOLUTION: The device is composed of a light guide body 3 which guides light from a primary light source and emit it at an angle from an emitting face and a light polarization element 4 installed adjacent to a light-emitting face 33 of the light guide body. Multiple parallel rows of prisms are formed on a light incident face 41 of the light polarization element. Assume a row I of virtual prisms arranged with the same pitch as the row of prisms and configure an apex angle θ of the virtual prism so that virtual light grazing the crowning of an adjacent virtual prism row toward the direction of a peak output light from the light-emitting face 33 enters from a prism face I-1 and outputs to the direction of a normal line of the output face after being totally reflected at the inside face of a virtual prism face I-2. The prism surface of the light incident face 41 is formed in a concave curve configuring the angle of inclination bigger than the angle made by the virtual prism face I-2 and the light output face 42 at the point further from the light output face 42 than the point K2 where the virtual light is totally reflected internally.