device for varying temperature all foer to an optical lens in oenskat laege in a linsfattning

摘要

An optical lens (2) is kept in a desired position in a lens holder (1) by a means (3). The back of the lens engages against a fixed abutment (4) and the means (3) has a tubular keeper (5) which is threaded (6) into the holder (1). The keeper (5) is divided by slits (7a) into deflectable supports (7). These are kept in engagement against the peripheral surface (8) of the lens (2) by a ring (9) which is a part of the means (3). The thickness (t) and width of the supports (7) are selected such that they are practically stiff in a tangential direction and yielding in a radial direction. To have low weight, the holde (1) and keeper (5) are of aluminium. The lens (2) is of glass and the ring (9) of titanium, the coefficient of linear expansion of which agrees closely with that of the glass. For temperature variations, the holder (1) and keeper (5) will be subjected to relatively large change in length, while the ring (9) keeps the engagement surfaces (10) of the supports (7) in engagement against the peripheral surface (8) of the lens (2). A diametrically opposed pair of the supports (7) then keeps the optical axis (C) of the lens in its position in the holder (1) in the tangential direction of the supports.