To provide an optical sheet, which has a concavo-convex pattern formed on a side face part where light is incident and which can be inexpensively produced, and to provide a surface light source device and a transmissive image display device having the optical sheet, and a production method of the optical sheet.
A light guide plate 30 comprises: a main sheet 31; and a projection stripe sheet 50. The main sheet 31 has a side face where light from an LED light source enters and an exit face where the light exits, formed in a direction intersecting the side face. The projection stripe sheet 50 includes projection stripes 51 formed on one surface 50a, the projection stripes extending in a thickness direction of the light guide plate 30 and arranged in parallel to one another in a direction orthogonal to the extending direction. In the projection stripe 51, a ratio of the width W51 to the height H51 is from 0.289 to 0.596. The projection stripe sheet 50 is disposed on a side face of the main sheet 31 with an adhesive 40, allowing the one surface 50a to oppose to the LED light source. The light from the LED light source enters the side face of the main sheet 31 via the projection stripe sheet 50.
OTA HIROSHI
SUMIYA HIDENORI
KAWAKAMI TAKESHI
Yoshinori Shimizu
Takashi Mikami