TOTAL INTERNAL REFLECTION PRISM UNIT TOTAL INTERNAL REFLECTION PRISM ASSEMBLY INCLUDING THE SAME AND APPARATUS FOR FORMING A LINE BEAM INCLUDING THE SAME

摘要

A total-reflection prism unit includes first and second prisms. The first prism includes a first total-reflection surface totally reflecting incident light, which is emitted in a first horizontal direction, in a second horizontal direction which is orthogonal to the first horizontal direction; and a second total-reflection surface forming a first beam by totally reflecting the light, which has been totally reflected from the first total-reflection surface, in the first horizontal direction. The second prism includes: a third total-reflection surface totally reflecting the light in a third horizontal direction which is orthogonal to the first horizontal direction; and a fourth total-reflection surface forming a second beam, which is separated from the first beam in the third horizontal direction, by totally reflecting the light, which has been totally reflected from the third total-reflection surface, in the first horizontal direction. Therefore, since the prisms have a parallelepiped shape which is easy to process, the homogeneity of a line beam can be prevented from being degraded due to poor processing.