Article: Front Surface Mirrors For Optics

What Is A Front Surface Mirror?

First let us define what a mirror is and then we can explain what a front surface mirror is.

A mirror is any specularly reflecting surface, and in most large volume applications this reflective medium is aluminum coating. A back surface mirror has the reflective coating on the surface opposite the viewing surface, so it's imperative that the substrate be transparent. In most cases the substrate is glass and the aluminum based coating has a protective coating over it that helps to protect it from damage it might receive during transport or installation.

Back surface mirrors are very useful for reflecting light in commercial applications such as a mirror mounted on a wall for personal grooming. These are considered low precision mirrors because they actually have two reflecting surfaces. The first reflecting surface is the initial surface on the pane of glass where a small percentage of light is reflected off the surface. The second reflecting surface is the aluminum coating where a high percentage of light is reflected off the surface.

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