Why Use Front Surface Mirrors - Thin Metal Films Ltd.

The main difference between the domestic mirror (rear surface mirror) and the front surface mirror is that a secondary or ghost image can be generated on the first surface of the rear surface mirror, especially when operating at an angle - for example:

Front Surface Mirror

The ghost image of the Rear Surface Mirror is highly detrimental to the image quality of your optical system. The reflectivity of the Front Surface Mirror is much higher than for the Rear Surface Mirror, thus greatly improving the efficiency of the system.

How are they made?

We can make front surface mirrors out of several ultra pure metals (see here for specification) which is evaporated under carefully controlled conditions in a high vacuum chamber, which contains the selected substrate to be coated. The metal vapour condenses onto the cold substrate to form a solid but very thin layer which replicates the substrate surface exactly. Hence it is very important that the substrate is free from any surface defects, such as scratch, seeds, ripples or finger marks.

Aluminium and other metal coatings can be soft - so they can be difficult to handle without damaging the coating. To overcome this problem TMF add a protective overcoat which allows your to handle and clean the mirror. Please see our cleaning procedure for front surface mirrors.

What Sizes can I have?

Our largest vacuum chamber has a maximum working dimension of 3m x 1.8m (118"x70"). So providing the glass or substrate is available, you can have any size up to the maximum.

Glass and substrate thickeness should be chosen to suit the application, however we can supply mirrors on 1, 2, 3, 4, 6 and 10mm glass. Other thicknesses and substrates are available upon request.

We can also coat your own optical components with this coatings to suite a wide range of optical applications.