Product description

Effect of light a plane lens degree has many causes. Roughness will mirror caused by incident light diffusion, reduce the lens transmittance. In addition the material absorption of optical activity, also will cause a certain incident light source which is particularly serious part frequency dissipation. For example, absorbs red light material looks green. But these factors, can be removed as much as possible. 　It is a pity that the defect nature already exists. When the incident light through a different medium, will cause reflection and refraction problem. If we vertical incidence of material, we can define the reflectance and transmittance.

Film refractive index

In fact, the two problems are consistent. As long as we can understand the first problem, other natural will be smoothly done or easily solved.

According to the basic theory of electromagnetism, mentioned for the transmission and reflection of different medium.

If the medium N1 vertical incidence to N2

Reflectivity = [(N2 N1) / (n1+n2)

The penetration rate = 4n1n2 / (n1+n2) 2

（1）Enter the glass directly by air

The penetration rate = 4 * 1 * 1.8 / 2 = 91.84% (1+1.8)

（2）Into the glass and then by air to enter after coating

The penetration rate = [4 x 1 x 1.5 / (1+1.5) 2] * [4 * 1.5 * 1.8 / (1.5+1.8) 2] = 95.2%

Visible coated glass will increase transparency. In addition the formula, we can calculate the light penetrating the two sides lens, found that even a perfect lens (index 1.8), the transmittance of about 85%. If you add a layer of coating (index 1.5), then the transmittance can reach 91%.

Coating thickness

Finally, we will explore the coating thickness is different, what effect can you have? We already know that the refraction of light transmittance and deposition rate, but not about its thickness. But if we can in the coating thickness at work, will find that reflected light A and optical path difference reflected light B NC * 2D difference. If

nc×2D＝（N+ 1/2）λ The N= 0,1,2,3,4,5..... Lambda light wavelength in air

Reflection will result in the light of specific wavelengths have destructive effects, so the reflected light color will change.

In many complex optical systems, the inhibition of the reflected light is very important homework. So a group of lens between the coating thickness, will use different to reflect light elimination of different frequency. Optical system more advanced so, found that the reflected light color will be more.

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