An optical diffusing sheet is provided, which prevents deterioration in image quality which might result from warping of the sheets due to environmental changes, and is capable of, even if a substrate is broken by an accident, preventing scattering of pieces of the broken substrate. The hardness of the gasket 4, the angle between the tapered faces 7a, 7b of the ridge 7, the height of the ridge 7 and the area of the flat top end face 7c of the ridge are so determined that the value of thrust for tightening up the coupling is between a predetermined minimum value and a predetermined maximum value. A water-insoluble heavy metal soap is incorporated into the chamber in an amount effective to reduce the PAV-DSR temperature of the asphalt base material by an incremental amount of at least 1\xb0 C. According to the present invention, a liquid crystal display apparatus can be obtained in which the illuminance on the screen when an image is displayed using a backlight can be enhanced without increasing light amount from the backlight, efficiency in using backlight can be improved and the production costs can be reduced. The basket has an upper opening and a lower opening.