LIGHT TRANSMISSION PLATE AND SURFACE LIGHT DEVICE AND DISPLAY DEVICE USING THE LIGHT TRANSMISSION PLATE

摘要

PROBLEM TO BE SOLVED: To provide a light transmission plate having a light entering face with the width larger than the thickness of the exiting face portion in which a light light can be efficiently condensed while the light incident to the entering face is suppressed from exiting from the entering face, and to provide a surface light source device and a display device that the aforementioned light transmission plate is used and the light incident to the entering face can be effectively used. SOLUTION: This device is equipped with a slope 14 disposed between an entering face 11 and an exiting face 12, facing the entering face 11 and in contact with the exiting face on the side line, or is equipped with a slope 15 disposed between the entering face 11 and a back face 13, facing the entering face 11 and in contact with the back face 13 on the side line. By controlling the inclination of the slope 14 or 15 to an angle θ satisfying a prescribed condition equation, the light incident to the entering face is suppressed from outgoing from the entering face.