Consideration

Issue - Material (Optical Glass Substrate & targets)

Optical Glass Substrate

Optical Function:
See optical glass specification and design reference, or contact us.

Thickness:
The manufacture make optical glass usually in a very big size more than 500mm*600mm. The secondary processor will re-size original glass into desired size. However, thickness is base on the original production status and usually will not process again. (Because processing thickness is very expensive and high risk). The product designer usually have to choice the exist thickness of glass in the market.

Property:
Each kind of optical glass have its own composition material. And this make the difference in physical and chemical properties. Some can stand acid-environment, some can stand for alkaline. Some can stand for hot. It have to be carefully selected by working environment of the applied product.

Surface Quality:
Surface quality is part of the property but will be consider as a special issue. Although the surface quality usually will not influence the optical spectrum function. But it is possible to be considered as a major acceptance criteria. Some glass easy to be scratched. Some may have lots of small digs. Some may easily generate mist on surface. If you did not care surface quality, you could choice cheap glass. If you care, the good surface quality glass usually much expensive than the bad one.
The process method to change surface quality is only by polishing. Use some grinding material to contact and polish the surface of glass. By this way, can remove top part surface of glass. But this work is very expensive. And will not suggest to use.

Glass Type and Manufacturer Information
The table below only lists some popular optical glass in market which is easy to purchase. If you need other kind of glass, please contact us for further information..

Thickness Table

Note: Borofloat have 1.2,1.35, 1.5, 1.65, 1.85, 2.0, 2.5, 3.0, 3.5 ~ 17.0 mm thickness

Targets

The tragets is a composition material of thin film which attached on the substrate. One layer of matel target usually can make reflection or decroation effect. (there are also some skills to do multilayers by only one target material) Two types(material) layers can make the effect of interference.(Three types material is rare to use, its analysis simulation and practical implement is much difficult than two types).

The target we select is base on the spectrum consideration (refractive index, absorption) . The price and some physic and chemical characteristic (adhesive force, durable for hot, durable for chemical enviroment) also will be considered. However, It will be in the internal consideration of coating producer. The customer usually need not to involve this issue. But it will be a critical issue for coating OEM producer to accept your product or not. The coating OEM producer usually familiar to some materials they used before. And for vacuum thin film coater, It is not good to change a new type target material. It is very possible to pollute between new and old target materials. It is very difficult to clean the target in the coater and possible to pollute each other. The coating OEM producer usually will refuse the product if they feel the pollution problem can't be overcomed.

There are many target materials used in optical thin film coating. It can be classified into four major types. Metal Target, Metal - Oxide, Non Metal- Oxide, Metal - fluoride. As a target material, the purity is important. the purity of 99.99~99.9999% is basic requirement for coating needed. If the purity is not good, it certainly influence the effect of coating layers. And always fail your products.