why should we use canadabalsem to glued lenses
Answers
Answered by
9
turpentine or balsam of fir, is a turpentinemade from the resin of the balsam fir tree (Abies balsamea) of boreal North America. The resin, dissolved in essential oils, is a viscous, sticky, colourless or yellowish liquid that turns to a transparent yellowish mass when the essential oils have been allowed to evaporate.
Canada balsam is amorphous when dried. Since it does not crystallize with age, its optical properties do not deteriorate.[citation needed] However, it has poor thermal and solvent resistance.[1]
Canada balsam is amorphous when dried. Since it does not crystallize with age, its optical properties do not deteriorate.[citation needed] However, it has poor thermal and solvent resistance.[1]
Answered by
10
Due to its high optical quality and the similarity of its refractive index to that of crown glass (n = 1.55), purified and filtered Canada balsam was traditionally used in optics as an invisible-when-dry glue for glass, such as lens elements. Lenses glued with Canada balsam (or with other similar glues) are called cemented lenses. Also, other optical elements can be cemented with Canada balsam, such as two prisms bonded to form a beam splitter. Balsam was phased out as an optical adhesive during World War II, in favour of polyester, epoxy, and urethane-based adhesives. In modern optical manufacturing, UV-cured epoxies are often used to bond lens elements.
Attachments:
Similar questions