GB1225035A - Optical viewing systems - Google Patents

Abstract

1,225,035. Optical viewing systems. BARR & STROUD Ltd. March 14, 1969 [March 15, 1968], No. 12579/68. Heading G2A and G2J. An optical viewing system for use with a telescope or periscope comprises a body having a pair of eye-pieces 7, 8 mounted thereon and a camera position 25 provided therein, a pair of rhomboid prisms 1, 2 mounted in the body to receive light from a viewed object and means for adjusting the position of the prisms to selectively direct light to one eye-piece 1<SP>1</SP>, 2<SP>11</SP>, to both eye-pieces 1<SP>1</SP> 2<SP>1</SP> or to one eye-piece and the camera position 1<SP>11</SP>, 2<SP>1</SP>. The prisms 1, 2 are disposed in parallel vertical planes lying at right angles to the main optical axis 00 about which the prisms are rotatable with the reflecting surface 5 of prism 1 and the beamsplitting surface 3 of prism 2 centred thereon. When used for photography as shown in Fig. 1, and position 1<SP>11</SP>, 2<SP>1</SP> in Fig. 2 light entering the system is split at surface 3 so that part is transmitted to prism 1 to be reflected upwardly by surface 5 to surface 6 which directs the light through aperture 25 into a camera 24 and part is reflected downwardly to surface 4 of prism 2 which directs the light into the left eye-piece 8. For binocular use 1<SP>1</SP>, 2<SP>1</SP>, Fig.2, prism 1 is pivoted, about axis 00 to a second stable position 1<SP>1</SP>, in which both prisms are disposed downwardly from axis 00 and are equally inclined to but on opposite sides of the vertical plane through axis 00. This is achieved by rotating a lever 14 connected by a sprung roller (28), Fig. 4 (not shown) and gearing 11, (12, 13), Fig. 3 (not shown) to a shaft 10 which carries prism 1 so that light transmitted by prism 2 is reflected into the right eye-piece 7. Iriterocular distance may be adjusted by pivoting prism 1 and eye-piece 7 together about the main axis 00 along curve C. This is acheived by rotating a lever 26 associated with a bracket 16 which supports the eye-piece 7, is engageable with the holder of prism 1 and is rotatable about shaft 10. For monocular use 1<SP>1</SP>, 2<SP>11</SP>, Fig.2 prism 2 is pivoted to a position 2<SP>11</SP> out of alignment with the main optical axis 00 by rotating its associated lever 22 and supplementary lenses 23 are introduced into the right eye-piece 7 to maintain the focusing thereof.