BRIGHTNESS ENHANCEMENT FILM FOR BACKLIT IMAGE DISPLAYS

摘要

A brightness enhancement film (22A) having a monolayer of approximately hemispherical, transparent, closely packed larger diameter hemi-beads (24). Due to the hemi-beads' hemispherical shape, gaps (26) remain between adjacent ones of the larger diameter hemi-beads. A substantial number of the gaps are provided with at least one approximately hemispherical, transparent hemi-bead (28) having a diameter substantially less than the diameter of the larger diameter hemi-beads. Provision of smaller diameter hemi-beads within the gaps increases the film's reflectance value, such that the film's apparent brightness declines as a relatively smooth, continuous function of viewing angle, for viewing angles ranging from 0° (normal incidence) to about 40°, which is the preferred angular viewing range.