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.

This dual reflection effect of a low precision mirror causes a loss of contrast and image distortion that is undesirable in high precision applications like rear projection systems, scanners and reflecting telescopes. In these cases good image quality is highly preferred, and this is where a front surface mirror is desired for clarity and single image reflection.

A front surface mirror is similar in construction to the previous mirror described except in a few key ways. The first way is that the reflection coating is on the first surface of the glass pane (or possibly other substrates). The second way is that the reflection coating does not have an obstructive protective coating, but instead incorporates a protective aspect within the reflection coating.

Another key difference is the quality of the aluminum base coating that is used for the reflection surface. Front surface mirrors commonly use a much higher quality material that has a relatively high reflectance across a broad spectral band (visible). ZC&R front surface mirrors not only provide high quality and high reflectance, but are also comparably low cost and durable. ZC&R front surface mirrors pass humidity, adhesion, salt fog and cheesecloth abrasion tests.

For more information regarding Front Surface Mirrors please call 800.426.2864 or email us.

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This entry was posted by ZC&R, on Tuesday, June 16th, 2009 at 5:00 am and is filed under Optical Applications, Optical Coatings. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response below.