GB547761A - Improvements in means enabling submerged objects to be viewed or photographed with reduced refractive effects - Google Patents

Abstract

547,761. Optical apparatus. JOHNSON, E. R. F. July 3, 1941, No. 8412. Convention date, Oct. 26, 1940. [Class 97 (i)] Means enabling submerged objects to be viewed or photographed through the window of a diving bell, aquarium &c. with reduced distortion and refraction effects, comprises an auxiliary window movable with the viewer or camera so as to remain perpendicular to the optical axis, and means for maintaining between the two windows a medium having substantially the same refractive index as the medium in which the object is submerged. As shown a frame 15 is held tightly against a window 11 by bolts in the wall 10 and by nuts. A frame 21 is mounted on vertical pivots 19, 20 in the frame 15 and carries horizontal pivots 26 on which a frame 27, carrying an auxiliary window 42 and a camera 31, is adjustably mounted. A flexible bellows 45 is secured to the window 42, and between the frame 15 and the window 11, to form a liquid chamber which is connected to a tank 48 receiving liquid displaced by movement of the window 42. The camera may be replaced by a facehood for viewing, or the window 42 may be carried by the camera and the bellows be secured to the window 11 by a suction ring. For curved windows the bellows may be secured to the surrounding wall ; the liquid may be coloured to form a light filter.