| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface light source apparatus, which can prevent the appearance of a bright line and can attain a bright and even surface illumination. SOLUTION: A fluorescent lamp 5 is disposed to face an incident face 4 of a light guide plate 3. Light from the fluorescent lamp 5 enters the light guide plate 3 via the incident face 4 and transmits through the inside of the light guide plate 3. During the light transmission, part of the light whose incident angle with respect to an emission face 6 is smaller than a critical angle is emitted from the emission face 6 of the light guide plate 3. Plural prismatic projections 13 having triangular cross-section are formed on the rear face 11 of the light guide plate 3, and the prismatic projections 13 that are located in the proximity L of the incident face of the light guide plate 3 are roughened. With such configuration, the light reflected or refracted on the prismatic projections 13 of the light guide plate 3 is diffused on the roughened surface part in the proximity L of the incident face. Thus, a bright line which appears on the emission face 6 of the light guide plate 3 in the proximity L of the incident face becomes blurred and is made inconspicuous. |
