| 摘要 |
FIELD: physics. ^ SUBSTANCE: protective blind consists of a housing, flat diaphragms and an optically transparent solid layer which fills the entire free space between any two neighbouring diaphragms. The housing, diaphragms and optically transparent solid layer are made from materials which are chemically resistant to effects of vapour, aqueous alkali solutions and concentrated acid solutions, including hydrofluoric acid. The optically transparent solid layer has a selective light transmission (absorption) coefficient. The free space inside the blind is filled with gas (or mixture of gases) which is at pressure lower than ambient pressure. ^ EFFECT: increased reliability of the design of the optical blind and lens and retention of the given attenuation factor of the blind when used in a chemically aggressive medium. ^ 2 cl, 2 dwg, 2 ex |
