Roof Prisms

Rotate and reverse images and deflect light at 90° bends. Suitable for telescopes and any optical instrument that requires the image to be flipped from the objective, turned over to the right, and bent at 90° to maintain correct visual orientation.

Ridge prism is the key to the existence of the ridge surface, the so-called ridge surface is the light path inside will encounter a ridge shaped by two reflectors of the reflector, the two sides of the prism in the middle of the light path, so some ridge prism can see the middle of a dividing line, in fact, can also be understood as the beam divided into two halves and then combined.

Two reflecting surfaces perpendicular to each other are called ridge surfaces, and a prism with ridge surfaces is called ridge prisms. The roof prism is small and can position the objective and eyepiece in a straight line, so it is often used in extremely compact binoculars. A special variant of the pentaprism. On the basis of standard pentaprisms of 112.5° ~ 112.5° ~ 90° type, the upper plane of 112.5° is changed into two inclined planes of roof shape (combined to 90°) to make a reflection prism. [1]

Roof prism features

Ridge prism is the key to the existence of the ridge surface, the so-called ridge surface is the light path inside will encounter a ridge shaped by two reflectors of the reflector, the two sides of the prism in the middle of the light path, so some ridge prism can see the middle of a dividing line, in fact, can also be understood as the beam divided into two halves and then combined. When two mirrors form a right Angle, a roof surface is formed, and the most commonly used Biehan prism principle reflects six times. Correspondingly, there is a modern Zeiss telescope commonly used abbe prism, also a ridge prism, slightly longer, but only four reflections, and do not require reflective coating, so the efficiency is higher than the Biehan prism and the ordinary Paul prism about the same.

Roof surface action

Under the condition of not changing the optical axis direction and the imaging direction in the main section, one reflection is added to make the total number of reflections of the system change from odd to even, so as to achieve the requirement of object image similarity.