The mirror coating is applied to the rear surface of the mirror so light is passed through the substrate, reflected from the coating and then passed back through the substrate again. Generally speaking a front surface mirror has a higher reflective efficiency then a rear surface mirror. Another disadvantage of rear surfaced mirrors is that some light is reflected from the surface of the substrate forming a parasitic second reflection which causes a somewhat diffused looking return beam. A rear surface mirror is more durable since it is protected by the substrate but it needs a substrate of higher optical quality since the light has to pass through the substrate twice. Inc. All Rights Reserved.
Specifications are subject to change without notice.