Optical Glasses

光学玻璃

The most common types of glasses used in optics are crown glasses and flint glasses, designations based on their dispersions. Flint glasses contain lead. These designations are further subdivided by composition and have letter designations and number designations called "glass numbers".

在光学中常用的玻璃类型主要有火石玻璃和冕玻璃，这些名称是根据它们的色散特性来命名的。火石玻璃含有铅。这些名称进一步根据成分进行细分，并有称为“玻璃编号”的字母编号和数字编号。

Example data for glasses:

Glass 玻璃	Glass Number 玻璃数	Density gm/cm³ 密度 g/cm³
Borosilicate BK7 硼硅酸盐BK7	517642	2.51
Crown K5 Crown K5（专名或术语）	522595	2.59
Dense barium crown SK4 密实的钡冕SK4	618551	3.57
Dense flint SF6 密级 Flint SF6	805254	5.18

玻璃的示例数据：

Common crown glasses have indices of refraction around 1.5-1.6, while extra dense flint glass may have an index as high as 1.75 . Lenses of crown and flint glasses are often used in multi-component lenses because of their complementary properties. For example, a strong positive crown lens with its low dispersion may be used in a doublet with a weaker negative lens of flint glass (high dispersion) to correct for chromatic aberration.

常见的火石玻璃折射率约为1.5-1.6，而超密特玻璃的折射率可能高达1.75。由于其互补性质，火石玻璃和特玻璃制成的透镜常用于多元件透镜中。例如，一个强正透镜，其色散较低，可以与一个色散较高的弱负透镜（特玻璃）组成双透镜组，以校正色差。

The design of multi-component lenses requires very exacting specifications for the glasses used. Professional optics books have detailed tables of glasses with their glass numbers, densities, softening temperatures, etc. For example, Table 11.6a in Waynant & Ediger.

设计多组分透镜需要对使用的玻璃有非常严格的规定。专业光学书籍中有关于各种玻璃的详细表格，包括玻璃编号、密度、软化温度等。例如，Waynant & Ediger 的表11.6a。

Composition of Glasses

玻璃的组成

Glasses can be considered to be solutions, rather than chemical compounds. According to Meyer-Arendt, about 95% of all glasses are of the "soda-lime" type, containing silicon dioxide (silica), Na2O (soda), and CaO (lime). Crown glass is a soda-lime-silica composite. Flint glasses contain 45-65% lead oxide - they are high-density, high-dispersion, high-refractive-index glasses. There are glasses which have barium oxide rather than lead oxide; they are called barium glasses. Barium glasses have refractive indices comparable to the flints, but have lower dispersions. Other heavy elements are used to make flint glasses, such as lanthanum and the rare earths.

玻璃可以被视为溶液，而不是化学化合物。根据Meyer-Arendt的说法，所有玻璃中约有95%属于“钠钙硅”类型，含有二氧化硅（石英）、Na₂O（钠）和CaO（石灰）。皇冠玻璃是一种钠钙硅复合物。含铅氧化物的玻璃含有45-65%的铅氧化物，它们是高密度、高色散、高折射率的玻璃。还有一些玻璃使用氧化钡代替氧化铅，被称为钡玻璃。钡玻璃的折射率与铅玻璃相当，但色散较低。其他重元素也被用于制造铅玻璃，如镧和稀有元素。

As alternatives to silica glasses, other "glass formers" such as boron oxide (B2O5), phosphorus pentoxide (P2O5) and germanium oxide (GeO2) can be used.

作为硅玻璃的替代品，其他‘玻璃形成物’如硼氧化物（B₂O₅）、五氧化二磷（P₂O₅）和锗氧化物（GeO₂）也可以被使用。