Optic nerve lens optical

Pentaprism pentaprism is an optical prism with five reflecting surfaces, which can deflect the incident light by 90 °. The incoming light is reflected twice in the prism to change the direction by 90 °, which will not only not invert, but also change the partial chirality of the image. The ordinary right angle prism will invert the image and change the partial chirality.

The reflection inside the prism is not caused by total reflection, because the angle of the incident light at the time of reflection is less than the critical angle, that is, the minimum angle of total reflection, so both reflecting surfaces should be plated as reflecting mirrors; The incident and outgoing surfaces should be coated with anti reflection film to reduce reflection. Although the fifth surface is not used, the included angle with the two reflecting surfaces is an obtuse angle (greater than the internal angle of a right angle).

Amisi prism amisi prism is named after Italian astronomer Giovanni amisi. It is an optical prism with dispersion function and is often used in spectrometers. Amish prism consists of two triangular prisms. The first triangular prism is usually made of coronal glass with medium dispersion ability, and the second is made of flint glass with high dispersion. When the light enters the first prism, it is first refracted, then enters the interface between the two prisms, and then emits in a direction almost perpendicular to the surface of the second prism. The angle and material of the prism are selected so that the light of one wavelength (color), usually the central wavelength, leaves the prism parallel to the incident beam. The deflection angle of other wavelengths is related to the dispersion ability of the material. Observing a light source passing through a prism can show the optical spectrum of the light source

The variant of pentaprism is roof pentaprism, which is usually used in monocular camera. In this case, because the image projected on the fuselage will rotate 180 ° after the lens is focused, the light beam reflected from the plane mirror to the pentaprism after the focus also needs to change the left-right relationship of the image direction. This change can be completed by replacing one of the reflecting surfaces into a roof type reflecting surface. The two surfaces of the replaced roof prism intersect at 90 ° perpendicular to each other, which will change the partial chirality of the image.