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Penta Prism

A penta prism( pentagonal prism ) is a deviation prism that is used to deflect light by a constant angle of deviation. The deviation angle of 90 degrees will not be changed if the penta prism is slightly adjusted. The reflecting surfaces of this prism must be coated with a metallic or dielectric reflective coating. Penta prism provides excellent beam alignment, image clarity and appearance quality.Penta prism is widely used in in camera viewfinder, image observation system or measuring instrument. You are welcome to contact us for Custom Penta prism!

Description Of Penta Prism

Penta prisms allow precise deviation of the line of sight or input beam by 90° (±30 arcsecond accuracy). In imaging applications, penta prisms do not invert or reverse the image. These prisms deflect the beam by the same angle, regardless of its orientation relative to the beam. Penta prisms are especially valuable for applications that require precise 90° offsets without the need for precise orientation of the prisms. Due to their monolithic design, penta prisms are more stable than systems consisting of two mirrors.

Penta prisms cannot achieve total internal reflection based on the critical angle principle. Therefore, the two reflective surfaces of this prism are generally coated with aluminum film and black paint, and the incident surface and the outgoing surface are coated with MgF2 single anti-reflection coating.

Custom Penta Prism

Oplens supply high quality custom Penta prism made to our design or to your custom specification. Every component is individually tested by our highly skilled technicians using our Prism Master capable of 3 arc seconds accuracy to ensure all components meet our high quality standards. Penta prisms may also be bonded to wedges prisms or other components to create optical subassemblies. Please visit our custom capabilities pages for more information.


Beam Deflection Angle±3′
MaterialH-K9L/UV Fused Silica
Diameter Tolerance0/-0.1
Surface Flatnessλ /5
Clear Aperture>90%
LacquerGT-7 or equivalent