SURFACE LIGHT SOURCE DEVICE, IMAGE DISPLAY DEVICE AND LIGHT GUIDE PLATE

摘要

PURPOSE: To easily adjust the ratio of a light diffusion pattern to the other rough surface part even if the thickness of a light guide plate is reduced, and to obtain uniform surface illumination. CONSTITUTION: Since a rough surface pattern 14 formed at least on the back surface 12 side of the light guide plate 2 and functioning as an irregular light-diffusion pattern is formed of a number of fine projections 14a projecting from the reference surface of the guide plate 2 by reducing minus projections 14b recessed inside from the reference surface(back surface 12) of the guide plate 2, the travel of light propagating toward the tip side 21 of the guide plate 2 from the incident surface 4 side of the guide plate 2 is less hindered by the minus projections 14b of the pattern 14 even if the thickness of the guide plate 2 is reduced, so that the formation ratio of the pattern 14 to the rough surface part 15 can easily be adjusted.