To control the state of light emitted from an emission plane by forming plural scatter parts on at least one of a reflection plane and the emission plane so as to protrude them and appropriately changing the protruding height of the scatter parts.
On one side of a light guide plate 10 composed of a transparent plastic material, a lot of scatter parts 11 are provided so as to gradually enlarge its diameter from one end side, the respective scatter parts 11 are protruded from one side of the light guide plate 10, and the protruding heights of the scatter parts 11 are appropriately made different. When the area of the scatter parts 11 is too small, sufficient scattering can not be obtained and the quantity of light emitted from an emission plane 15 is reduced. When the area of the scatter parts 11 is too large, the shapes of the scatter parts 11 are viewed like being floated up. Therefore, it is preferable that the area of the scatter parts 11 is composed of the group of dots having area of within the grange of 0.01 to 20 mm2 and it is more preferable that the area is composed of the group of dots of within the range of 0.03 to 7 mm2. Further, it is preferable that these scatter parts 11 are regularly arranged.
FUKUDA KAZUHIRO
SAIGOU TAKAAKI
