Right Angle Prisms are commonly used to bend light at a 90° angle. When a light ray entering through one of the prism’s legs hits the glass/air boundary of the hypotenuse, total internal reflection occurs and the reflected light exits through the other prism leg. Images are inverted, but correct left-to-right. Precision Optical Systems offers N-BK7 Right Angle Prisms with a mirror coated hypotenuse surface, and AR coating on the legs to reduce surface loss and optimize the reflection.