Interferometric rotation sensor

Claim 2

A compound prism interferometer comprising: a first prism having a first planar face defining an entrance aperture for a light beam to enter said interferometer, a second planar face disposed parallel to said first planar face, a third planar face disposed opposite said first planar face and intersecting said second planar face at a first angle, a fourth planar face disposed opposite and parallel to said third planar face and intersecting said first planar face at said first angle; a second prism, a right-angle prism, having a fifth planar face, a sixth planar face disposed normal to said fifth planar face, and a seventh planar face opposite and intersecting said fifth and sixth planar faces at angles of 45*, said second prism being disposed adjacent said first prism with said fifth planar face and said second planar face being in face-to-face engaging relationship; a third prism, a right-angle prism, having an eighth planar face defining an exit aperture for said light beam, a ninth planar face disposed normal to said eighth planar face, and a tenth planar face opposite and intersecting said eighth and ninth planar faces at angles of 45*, said third prism being disposed adjacent said second prism with said tenth planar face and said seventh planar face being in face-to-face engaging relationship; and a fourth prism, a penta prism, having an eleventh planar face, a twelfth planar face intersecting said eleventh planar face at a second angle, a thirteenth planar face opposite said eleventh planar face and lying in a plane intersecting the plane of said twelfth planar face at a third angle, and a fourteenth planar face opposite said twelfth planar face, said twelfth and thirteenth planar faces being reflective for causing internal reflection of light within said fourth prism; said fourth prism being disposed adjacent first and third prisms with said fourteenth planar face being optically coupled to said third planar face and said eleventh planar face being in face-to-face engaging relationship with said ninth planar face whereby said light beam upon entering said first prism through said entrance aperture strikes said third planar face which divides it into a reflected beam and a transmitted beam, said reflected beam being reflected in the direction of said fourth planar face and being in turn reflected by said fourth planar face through said second planar face and said second and third prisms to said exit aperture, said transmitted beam passing through said third planar face into said fourth prism and being reflected by said twelfth planar face in the direction of said thirteenth planar face and thence being reflected by said thirteenth planar face through said eleventh planar face to said tenth planar face whereby it is reflected to said exit aperture, said reflected and transmitted beams being combined at said exit aperture to develop an interference fringe pattern.

Claim 3

An optical direction sensing system for determining the angular deflection between the input optical axis of said sensing system and the line of sight to a remote light source, comprising: a compound-prism interferometer means responsive to light from said source for generating an interference fringe pattern having a number of fringes related to the angular deviation between said input optical axis and said line of sight; and a fringe counting means responsive to said fringe pattern for generating an output signal commensurate with the number of fringEs in said fringe pattern; said compound-prism interferometer means comprising; a first prism having a first planar face defining an entrance aperture for a light beam to enter said interferometer, a second planar face disposed parallel to said first planar face, a third planar face disposed opposite said first planar face and intersecting said second planar face at the first angle, a fourth planar face disposed opposite and parallel to said third planar face and intersecting said first planar face at said first angle; a second prism, a right-angle prism, having a fifth planar face, a sixth planar face disposed normal to said fifth planar face, and a seventh planar face opposite and intersecting said fifth and sixth planar faces at angles of 45*, said second prism being disposed adjacent said first prism with said fifth planar face and said second planar face being in face-to-face engaging relationship; a third prism, a right-angle prism, having an eighth planar face defining an exit aperture for said light beam, a ninth planar face disposed normal to said eighth planar face, and a tenth planar face opposite and intersecting said eighth and ninth planar faces at angles of 45*, said third prism being disposed adjacent said second prism with said tenth planar face and said seventh planar face being in face-to-face engaging relationship; and a fourth prism, a penta prism, having an eleventh planar face, a twelfth planar face intersecting said eleventh planar face at a second angle, a thirteenth planar face opposite said eleventh planar face and lying in a plane intersecting the plane of said twelfth planar face at a third angle, and a fourteenth planar face opposite said twelfth planar face, said twelfth and thirteenth planar faces being reflective for causing internal reflection of light within said fourth prism, said fourth prism being disposed adjacent first and third prisms with said fourteenth planar face being optically coupled to said third planar face and said eleventh planar face being in face-to-face engaging relationship with said ninth planar face whereby said light beam upon entering said first prism through said entrance aperture strikes said third planar face which divides it into a reflected beam and a transmitted beam, said reflected beam being reflected in the direction of said fourth planar face through said second planar face and said second and third prisms to said exit aperture, said transmitted beam passing through said third planar face into said fourth prism and being reflected by said twelfth planar face in the direction of said thirteenth planar face and thence being reflected by said thirteenth planar face through said eleventh planar face to said tenth planar face whereby it is reflected to said exit aperture, said reflected and transmitted beams being combined at said exit aperture to develop an interference fringe pattern.

Claim 4

An optical direction sensing system for determining the angular deflection between the input optical axis of said sensing system and the line of sight to a remote light source, comprising: a compound-prism interferometer means responsive to light from said source for generating an interference fringe pattern having a number of fringes related to the angular deviation between said input optical axis and said line of sight; and a fringe counting means responsive to said fringe pattern for generating an output signal commensurate with the number of fringEs in said fringe pattern; said compound-prism interferometer means comprising; a first prism having a first planar face defining an entrance aperture for a light beam to enter said interferometer, a second planar face disposed parallel to said first planar face, a third planar face disposed opposite said first planar face and intersecting said second planar face at the first angle, a fourth planar face disposed opposite and parallel to said third planar face and intersecting said first planar face at said first angle; a second prism, a right-angle prism, having a fifth planar face, a sixth planar face disposed normal to said fifth planar face, and a seventh planar face opposite and intersecting said fifth and sixth planar faces at angles of 45*, said second prism being disposed adjacent said first prism with said fifth planar face and said second planar face being in face-to-face engaging relationship; a third prism, a right-angle prism, having an eighth planar face defining an exit aperture for said light beam, a ninth planar face disposed normal to said eighth planar face, and a tenth planar face opposite and intersecting said eighth and ninth planar faces at angles of 45*, said third prism being disposed adjacent said second prism with said tenth planar face and said seventh planar face being in face-to-face engaging relationship; and a fourth prism, a penta prism, having an eleventh planar face, a twelfth planar face intersecting said eleventh planar face at a second angle, a thirteenth planar face opposite said eleventh planar face and lying in a plane intersecting the plane of said twelfth planar face at a third angle, and a fourteenth planar face opposite said twelfth planar face, said twelfth and thirteenth planar faces being reflective for causing internal reflection of light within said fourth prism, said fourth prism being disposed adjacent first and third prisms with said fourteenth planar face being optically coupled to said third planar face and said eleventh planar face being in face-to-face engaging relationship with said ninth planar face whereby said light beam upon entering said first prism through said entrance aperture strikes said third planar face which divides it into a reflected beam and a transmitted beam, said reflected beam being reflected in the direction of said fourth planar face through said second planar face and said second and third prisms to said exit aperture, said transmitted beam passing through said third planar face into said fourth prism and being reflected by said twelfth planar face in the direction of said thirteenth planar face and thence being reflected by said thirteenth planar face through said eleventh planar face to said tenth planar face whereby it is reflected to said exit aperture, said reflected and transmitted beams being combined at said exit aperture to develop an interference fringe pattern.

Claim 5

An optical direction sensing system as recited in claim 2 and further comprising a servo system responsive to said output signal and operative to maintain said line of sight substantially coincident with said input optical axis.

Claim 6

A compound prism interferometer comprising: a first prism having a first planar face defining an entrance aperture for a light beam to enter said interferometer, a second planar face disposed parallel to said first planar face, a third planar face disposed opposite said first planar face and intersecting said second planar face at a first angle, a fourth planar face disposed opposite and parallel to said third planar face and intersecting said first planar face at said first angle; a second prism, a right-angle prism, having a fifth planar face, a sixth planar face disposed normal to said fifth planar face, and a seventh planar face opposite and intersecting said fifth and sixth planar faces at angles of 45*, said second prism being disposed adjacent said first prism with said fifth planar face and said second planar face being in face-to-face engaging relationship; a third prism, a right-angle prism, having an eighth planar face defining an exit aperture for said light beam, a ninth planar face disposed normal to said eighth planar face, and a tenth planar face opposite and intersecting said eighth and ninth planar faces at angles of 45*, said third prism being disposed adjacent said second prism with said tenth planar face and said seventh planar face being in face-to-face engaging relationship; and a fourth prism, a penta prism, having an eleventh planar face, a twelfth planar face intersecting said eleventh planar face at a second angle, a thirteenth planar face opposite said eleventh planar face and lying in a plane intersecting the plane of said twelfth planar face at a third angle, and a fourteenth planar face opposite said twelfth planar face, said twelfth and thirteenth planar faces being reflective for causing internal reflection of light within said fourth prism, said fourth prism being disposed adjacent first and third prisms with said fourteenth planar face being optically coupled to said third planar face and said eleventh planar face being in face-to-face engaging relationship with said ninth planar face; a fifth prism, a right-angle prism, having a fifteenth planar face, a sixteenth planar face disposed normal to said fifteenth planar face, and a seventeenth planar face which intersects the planes of said fifteenth and sixteenth faces, said sixteenth planar face being larger than said fifteenth planar face; said fifth prism being disposed adjacent said first prism and said fourth prism, said third planar face being in face-to-face engaging relationship with said seventeenth planar face, and said fourteenth planar face being in face-to-face engaging relationship with said sixteenth planar face; said fourth prism being disposed adjacent said third prism with said eleventh planar face being in face-to-face engaging relationship with said eleventh planar face whereby said light beam upon entering said first prism through said entrance aperture strikes said third planar face which divides it into a reflected beam and a transmitted beam, said reflected beam being reflected in the direction of said fourth planar face and being in turn reflected by said fourth planar face through said second planar face and said second and third prisms to said exit aperture, said transmitted beam passing through said third planar face into said fourth prism and being reflected by said twelfth planar face in the direction of said thirteenth planar face and thence being reflected by said thirteenth planar face through said eleventh planar face to said tenth planar face whereby it is reflected to said exit aperture, said reflected and transmitted beams being combined at said exit aperture to develop an interference fringe pattern.

Claim 7

A compound prism interferometer comprising: a first prism having a first planar face defining an entrance aperture for a light beam to enter said interferometer, a second planar face disposed parallel to said first planar face, a third planar face disposed opposite said first planar face and intersecting said second planar face at a first angle, a fourth planar face disposed opposite and parallel to said third planar face and intersecting said first planar face at said first angle; a second prism, a right-angle prism, having a fifth planar face, a sixth planar face disposed normal to said fifth planar face, and a seventh planar face opposite and intersecting said fifth and sixth planar faces at angles of 45*, said second prism being disposed adjacent said first prism with said fifth planar face and said second planar face being in face-to-face engaging relationship; a third prism, a right-angle prism, having an eighth planar face defining an exit aperture for said light beam, a ninth planar face disposed normal to said eighth planar face, and a tenth planar face opposite and intersecting said eighth and ninth planar faces at angles of 45*, said third prism being disposed adjacent said second prism with said tenth planar face and said seventh planar face being in face-to-face engaging relationship; and a fourth prism, a penta prism, having an eleventh planar face, a twelfth planar face intersecting said eleventh planar face at a second angle, a thirteenth planar face opposite said eleventh planar face and lying in a plane intersecting the plane of said twelfth planar face at a third angle, and a fourteenth planar face opposite said twelfth planar face, said twelfth and thirteenth planar faces being reflective for causing internal reflection of light within said fourth prism, said fourth prism being disposed adjacent first and third prisms with said fourteenth planar face being optically coupled to said third planar face and said eleventh planar face being in face-to-face engaging relationship with said ninth planar face; a fifth prism, a right-angle prism, having a fifteenth planar face, a sixteenth planar face disposed normal to said fifteenth planar face, and a seventeenth planar face which intersects the planes of said fifteenth and sixteenth faces, said sixteenth planar face being larger than said fifteenth planar face; said fifth prism being disposed adjacent said first prism and said fourth prism, said third planar face being in face-to-face engaging relationship with said seventeenth planar face, and said fourteenth planar face being in face-to-face engaging relationship with said sixteenth planar face; said fourth prism being disposed adjacent said third prism with said eleventh planar face being in face-to-face engaging relationship with said eleventh planar face whereby said light beam upon entering said first prism through said entrance aperture strikes said third planar face which divides it into a reflected beam and a transmitted beam, said reflected beam being reflected in the direction of said fourth planar face and being in turn reflected by said fourth planar face through said second planar face and said second and third prisms to said exit aperture, said transmitted beam passing through said third planar face into said fourth prism and being reflected by said twelfth planar face in the direction of said thirteenth planar face and thence being reflected by said thirteenth planar face through said eleventh planar face to said tenth planar face whereby it is reflected to said exit aperture, said reflected and transmitted beams being combined at said exit aperture to develop an interference fringe pattern.