| 摘要 |
PURPOSE: To facilitate the production of a light transimission plate, and the attachment of a light transmission plate to a light non-emitting type display device and to improve the visibility of a reflection type and light non-emitting type display device. CONSTITUTION: On the light transmission plate 10A, mutually parallel peak line T and a valley line V exist alternately on a surface 10d opposite to a flat surface 10a, and a prism array existing on virtual flat surfaces A1 and A2 where the valley line and the peak line are parallel with the flat surface 10a is formed. Then, an angle αformed by an inclined surface S1 on either side of each prism of the prism array with the virtual flat surface A1 is nearly equal to the critical angle of the light transmission plate to air, and an angle βformed by an inclined surface S2 on the other side of each prism of the prism array with the virtual flat surface A1 is about 2 deg.. It is more preferable that the angle β is <=10 deg. and is made larger as it aparts a straight tube type illumination lamp 12. This light transmission plate 10A is applicable to a surface light source for both of transmission type and reflection type liquid crystal display devices. |
