US2085026A - Prism - Google Patents

Description

88. UlllUb QUal bll Huuu June 29, 1937. 0. K. KASPEREIT 2,085,026

PRISM Filed Nov. 14, 1955 T 2 5 37 i Y 9 Inventor Elttm K Kaspareit Attorney Patented June 29, 1937 UNITED STATES PATENT OFFICE 1 Claim.

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

The subject of this invention is a prism designed primarily to deviate the line of sight through an angle of 90 in the horizontal plane and through an angle of 45 in the vertical plane and neither invert nor revert the image.

The prism is so designed as to be constructed of one piece of glass.

A practical embodiment of the invention is illustrated in the accompanying drawing, wherein:

Fig. 1 is a plan view.

Fig. 2 a side elevation, and

Fig. 3 an end elevation.

Referring to the drawing by characters of reference:

The prism is so formed that the angle alpha is equal to 22 30, the angle beta is equal to 45, the angle gamma is equal to 90 and the angle delta is equal to 112 30.

There is provided an entrant face I of quadrangular formation, opposite which is the reflecting face 2 making an angle of 45 with the face I. An upper inclined face 3 makes an angle of 45 with the face 2, while a face 4 parallel to the face I, and inclined end face 5 making an angle of 90 with the top face 3 and the faces 6 and 1, making an angle of 90 with each other and angles of 45 with the sides I and 4 respectively complete the prism.

From the foregoing it will be evident that the rays a, b and c which are rays emanating from points transverse of an object will enter the prism at the face I and be reflected at right angles from the face 2 to impinge upon the face 3 when they are again reflected at right angles, some to the face 6 and others to the face I, when those impinging upon the face 6 are reflected at 5 right angles to the face I, and those impinging upon the face 1 are reflected at right angles to the face 6 and from each of these faces the rays so reflected are again reflected to pass through the face 3 to the eye of the observer. 10

The rays a, d and e in the vertical plane pass through the face I and impinge upon the face 2, at which face they are reflected at right angles to the face 3. From the face 3 the rays are reflected at right angles to the faces 6 and l or the juncture of such faces and are then reflected at an angle of 45 through the face 3 to the eye of an observer.

I claim:

A prism embodying an entrant face, a reflecting face disposed at an angle of 45 to the entrant face, a second reflecting face disposed at an angle of 45 to the path of the rays of light reflected from the first reflecting face, the plane of the second reflecting face forming an angle of 45 with the plane of the first reflecting face, reflecting faces disposed at an angle of 90 to each other and forming a roof to intercept the rays reflected from the second reflecting face and inter-reflect the same to revert the image back to normal and reflect them through the emergent portion of the second reflecting face, the ridge of the roof extended forming with the central longitudinal axis of the second reflecting face extended an angle of 22 30'.

O'I'I'O K. KASPEREIT.

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