Abbe value

The dispersion is characterized by the difference in refractive indexes at various wavelengths. Most frequent use is made of the mean dispersion np — c) of the Abbe value v ... 

The refractive index values of solid oxides lie in the range of 1.3 to 2.7 with silicate glasses they vary between 1.5 and 1.9, while extreme values exhibited by special glasses are 1.35 and 2.25. The Abbe value lies in the range of 20 to 100. Current soda-Iime--silica and borosilicate glasses have 1.48 — 1.53 and v = 58 —70. The refractive index is increased most by PbO and BaO. The dispersion usually increases simultaneously with refractive index. 

Refractive Index, Abbe Value, Dispersion, and Glass Designation... 

For the conqtarison of glass types from different manufacturers, an abbreviated glass code is defined in the following way the first three digits correspond to d — 1, the second three digits represent the Abbe value Vd, and, after a dot, three more digits characterize the density (see Table 3.4-13). 

The designation of each glass type here is composed of an abbreviated family designation and a number. The glass families are arranged by decreasing Abbe value in the data tables (Table 3.4-14). 

Relationship Between the Abbe Value and the Relative Partial Dispersion. A linear relationship exists between the Abbe value and the relative partial dispersion for what are known as normal glasses ... 

The characterization of optical glasses through the refractive index and Abbe value alone is insufficient for high-quality optical systems. A more accurate description of the properties of a glass can be achieved with the aid of the relative partial dispersion. 

The changes in the refractive index and Abbe value caused by a change in the annealing rate are given by... 

The measurement accuracy of the Abbe value can be calculated using... 

Glass type Transparency range (p-m) Refractive index d Abbe value Vd Thermal expansion a (10"Vk) Microhardness HV Transformation temperature TgCC) Density e (g/cm )... 

Mycalex. Trade-name a particular type of MICA (glassbonded) (q.v.)- Mycalex and T.I.M. Ltd., Cirencester, England). Mylius Test. See iodoeosin test. n, Hjj, etc. Symbol for refractive index, the subscript indicates the spectral line to which the quoted value refers, e.g. n = the refractive index for a wavelength equivalent to the sodium D line, v-value. Alternative name for abbe value (q.v.). 

Abbe Number or Abbe Value. A measure of the optical diqiersion of a glass proposed by the German physicist E. 

Refractive index Abbe value Ve Stress-optical constant K (10- mm2/N)... 

Glass type Refractive index d Abbe value Vd ve Constants of the Sellmeier dispersion formula h II Cj... 

To interpolate refractive index values between measured points we used the Sellmeier or Cauchy equations (Smith, 1966). no, np and nc values were calculated with these equations and are shown, together with Abbe values, in the upper part of Table 3. Lower part of Table 3 show values of some glasses taken from data sheets (www.us.schott.com WWW. car gille. com). 

In Fig. 4 is shown the no - Abbe value diagram for the materials displayed in Table 3. Here we can notice that most of the ionic liquids have a lower refractive index than the glasses show. Notice that the ionic liquid MePyrr[HS04] shows a high Abbe number (91.3) and a refractive index of 1.465. These characteristics were useful when the design of multichamber lenses was done (Section 4). 

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