Introduction to metal dielectric film reflective lenses

Metal mirrors and metal dielectric mirrors are two different types of mirror filters with different film layer combinations. Let's explain them separately below.

What are the advantages of metal mirrors:

1. The high reflectivity band of metal mirrors is so wide that it can cover almost all optical frequency ranges. However, it should be noted that each type of metal reflector with different thin film types has its own best reflection band.

2. The adhesion ability between the metal film of different metal mirrors and the filter material varies. For example, aluminum film, chromium film, and nickel film have excellent firmness; The adhesion of gold film, silver film, and filter membrane is poor, so a layer of primer film is usually coated on the filter membrane substrate first.

3. The metal film of metal mirrors is easily corroded by environmental factors and has poor chemical stability.

4. The metal mirror film is soft and easy to scratch.

Dielectric film reflector

According to the characteristics of metal mirrors, a widely used metal dielectric mirror has emerged This mirror adopts a combination of metal film layer and dielectric film layer as high reflective film layer, and has the following characteristics:

1. It has a protective effect on metal thin films. Add a transition layer with good adhesion between the metal film and the filter substrate.

2. A high hardness and high transmittance transparent film is added between the metal film and the filter material.

The advantages of metal dielectric mirror filters are their simple structure and ease of mass production, but they also have disadvantages: they cannot achieve nearly 100% reflectivity. In ordinary high-power laser systems, the use of metal dielectric mirrors can cause the dielectric film to burn out due to their heat absorption.