OPTICAL ASSEMBLY WITH TRANSLATABLE CENTERED SLEEVE

摘要

Optical assemblies include a barrel defining a cavity having a center axis, a sleeve inserted in the cavity, one or more optical elements mounted within the sleeve and a retaining ring inserted into the cavity and securing the sleeve. The sleeve engages the barrel inner wall through a thread engagement allowing a longitudinal displacement of the sleeve within the cavity. The retaining ring is also threadably engaged within the barrel, and the profile of the corresponding threads, as well as the spatial profile of a peripheral transversal surface of the sleeve engaging the retaining ring, are selected to provide centering of the sleeve with respect to the center axis of the cavity throughout the longitudinal displacement of the sleeve.

主权项

1. An optical assembly, comprising:
a barrel defining a cavity having a center axis, the barrel comprising an inner wall provided with a first set of barrel threads and a second set of barrel threads; a sleeve inserted in the cavity and having a forward end and a rearward end, the forward end comprising an outer wall provided with a set of sleeve threads engaging the first set of barrel threads so as to allow a longitudinal displacement of the sleeve within the cavity upon rotation of the sleeve, the rearward end of the sleeve comprising a peripheral transversal surface having a curved spatial profile; at least one optical element mounted within the sleeve and centered with respect to the sleeve; and a retaining ring affixed to the barrel through a set of ring threads engaging the second set of barrel threads, the retaining ring having an abutment engaging the peripheral transversal surface of the sleeve, the ring threads having a rearward thread face forming an effective thread angle with respect to a plane perpendicular to the center axis of the cavity, wherein the effective thread angle of the ring threads and the curved spatial profile of the peripheral transversal surface are selected in view of an auto-centering condition whereby any decentering of the retaining ring and corresponding tilt of the retaining ring with respect to the center axis have counterbalancing effects on centering of the sleeve with respect to the center axis.