首页 >> 执行标准

DESIGNATION OF GLASS TYPES

We have strong capability to use various optical materials for optical components fabrication, so you can just let us know your applications if you have trouble in selecting proper material, and our engineers can help you select the material correctly.
Most of our raw materials come from the internationally renowned material suppliers, the materials we commonly employed are:

Guangming glass, Schott glass, Ohara glass, Hoya glass, Corning glass
Special glasses: Fused silica, Float glass, Zerodur...
Color glass (see color filter chapter for detail)
Crystal Glass (See Crystal chapter for detail)

The following contents you will learn how our colorless glass are equivalent to Schott, Hoya, or Ohara and some of their characteristic.

Character of the Colorless Optical Glass

Here RC (S), RA(S), FA and HK are respectively defined by the following rules.

RC(S) - Stability against Atmospheric Aquosity

Optical glass can be corraded by the wet atmosphere, then a degraded layer containing "White Speckle" and "Fog Turbidity" will appear on the surface. This layer scatters the parellel injection of beams more severely. Based on this experience, we can judge the degradation degree of optical glass by inspecting the scattering of the degraded layer. Tested by Chinese National Standard GB7962.15, we can get the turbidity degree expressed by "H" value. Compare the tested H value with the turbidity degree of BaK7 and ZK9,ie HBaK7 and HZK9, we can grade this stability into 4 levels as follows:

RA(S) - Stability against Acid Tested by Surface Method

The stability against acid is tested by Chinese National Standard GB7962.14. That is using PH2.9 Acetic Acid, PH4.6 Natrium acetic acid or PH6.0 distilled water as the corrasion substance, then record after how long the glass is in the corrasion substance the glass begins to present purple-blue interference spectrum. And we grade the glass into 6 levels.

PH Value PH 2.9 ± 0.2 PH 4.6 ± 0.2 PH 6.0 ± 0.2
Grade 1a 1b 2a 2b 3a 3b
After how long the interference spectrum presents ≥5h ＜5h, ≥0.5h ≥30min ＜30min, ≥5min ＞3h ≤3h

HK Knoop Hardness

Knoop Hardness is tested according to Chinese National Standard GB7962.21. Put a quarter diamond with symmetrical angles of 172°30' and 130°on the tested glass piece, then apply a certain press on the diamond for a certain duration, then abolish the press and measure the catercorner length of the deformed part. Calculate Knoop Hardness using the following formula:

Hk = 0.102F/(0.07028L2)

Among which
F press applied，N
Hk Knoop Hardness, Pa
L the catercorner length of the deformed part, mm

FA - Relative Anti-Rub Hardness

Elative Anti-Rub Hardness means the hardness of glass relative to K9 under the same rubbing conditions. This parameter is tested according to Chinese National Standard GB7962.19. Measure the loss volume of K9 after rubbing, noted as V0, and the loss volume of the tested glass after rubbing, noted as V. Their ratio shows the relative hardness of the tested glass, ie FA = V0/V.