Overview of Dielectric Mirrors

dielectric mirror

March 7, 2010

A dielectric mirror is a mirror that is comprised of multiple thin layers of dielectric material that are distributed on a glass surface. Dielectric material is a solid substance that does not conduct electricity and instead supports electrostatic fields. Dielectric material consists of solid materials which include glass, porcelain, plastics or the oxides of different types of metals.

Dielectric material supports electrostatic fields while dispersing a small amount of energy in the form of heat. If it maintains a minimal heat loss this increases the effectiveness of the dielectric material. The main function of dielectric material is to provide a myriad of reflective properties for the dielectric mirror surface by taking advantage of light beam interference derived from different optical interfaces.

   

Dielectric Coatings

beamsplitter mirror

There are different types of coatings for dielectric glass which are used in the creation of dielectric mirrors. These manufacturing techniques are based on thin film deposition which makes up the coatings on dielectric mirrors.

Material Evaporation: In this process the dielectric material is evaporated in a chamber using electron beam deposition which heats the dielectric material. This causes the evaporated material to transform to a substrate where it is heated to improve the quality of substrate dielectric material. Depending upon the type of dielectric material being heated it can become porous which can lead to problems for certain filter designs. This is the reason for using different types of dielectric material to serve different functions.

Ion Evaporation: This process of creating a dielectric glass coating is also known as ion-assisted deposition and works similar to the electron beam process except that it creates a denser coating from the dielectric material when the ion is applied to the target substrate.

Ion Beam Sputtering: This process is used to create an improved uniform coating of dielectric material that is void of porous qualities. The process involves applying an ion beam to metal or metal oxide to sputter dielectric material to the substrate. The result is improved adhesive quality and a smoother quality to the dielectric glass.

Advanced Sputtering: During this process the dielectric material is transformed into a high precision and dense coating through the process of metal oxidation sputtering. This procedure is also known as advanced plasma reactive sputtering and is similar to the previous evaporation techniques described only separate sources are used for the different types of dielectric coating materials.


Dielectric Mirror Designs

dielectric coating

The different coating processes that are used to create dielectric mirrors can sometimes make it difficult to locate a dielectric mirror with the required elements to serve a specific function. The type of design is often calculated with software that defines the different dielectric mirror properties. Dielectric mirror properties include the determination of reflectivity at different wavelengths and polarization which is based on beamsplitter technology, anti-reflection properties, and broadband reflection ranges.

Dielectric mirror properties are often determined with the use of specialized software that evaluates the properties based on a matrix method and by applying numerical algorithms and other analytical strategies. In addition to reflective optimization dielectric mirror design involves a balance of optical consideration and the required amount of layers and precision.

 

Dielectric Mirror Applications

dielectric glass

Dielectric mirrors are used for a number of purposes which is the primary reason that there are different types of dielectric materials and coating processes that are involved with the creation of dielectric mirrors. The different properties in dielectric glass design will determine the use of the mirror for different purposes.

Projectors: Dielectric mirrors are a primary component of video projectors and high definition televisions. They are also used for rear projection televisions and cinematography.

Mirror TV: Mirror televisions are flat screen high definition televisions that are concealed with a dielectric mirror. When the television is in use you can view the high definition quality through the dielectric mirror without sacrificing brightness due to a specific type of coating that is used for this purpose. When the TV is not in use the mirror projects a reflective quality that enhances your room décor.

Scientific Instruments: Different instruments that are used for science research utilize dielectric mirror technology. This includes instruments such as telescopes and other precision instruments that are used for scientific research as well as medical research.

There is also a variety of other uses for the dielectric mirror some of which are still currently under development. If you do some research you can find other interesting facts about dielectric technology manufacturing and the different ways that the technology is used to serve many purposes.