| 摘要 |
<p>A belt-driven tape cartridge having an optical element with at least two reflecting surfaces, and which is preferably an acrylic prism. The two reflecting surfaces are each disposed at predetermined angles that are substantially larger than a critical angle for the prism, wherein the critical angle is a property characteristic of the prism and determines the angle above which light is reflected instead of passed through. The inclusion of two reflecting surfaces and the choice of materials for the prism allows a substantially large range of angles for which the critical angle requirements is met.</p> |
