Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
100 words
A helmet mounted display system comprising: an eyepiece (3) through which a wearer of the helmet can directly view a forward scene (13) and which also serves to combine an intensified image of the forward scene (13) with the wearer's direct view of said scene, (13) characterised in that the intensified image is produced by an optical arrangement (4, 5, 6, 8) providing a light path substantially conforming to the profile (29) of the helmet and incorporating prism means (2) which serves to compensate for orientation of the intensified image in other parts of the optical arrangement (4, 5,6, 8).
Claim 2
Dependent Claim
67 words
A system according to Claim 1 wherein said prism means (2) comprises: a first face (17) through which light representing the intensified image passes to be incident on a second face (18) at which said light is reflected towards a third face (24) at which said light is internally reflected to be directed towards a fourth face (28) via which said light exits the prism means (2).
Claim 3
Dependent Claim
30 words
A system according to Claim 2 wherein said light representing said intensified image passes to said first face (17) via an adjacent wedge portion (2B) of said prism means (2).
Claim 4
Dependent Claim
52 words
A system according to Claim 2 or Claim 3 wherein said light representing said intensified image is produced in an image intensifier (6) coupled to said first face (17) of the prism means (2) via a first lens group (5) and to an objective lens (1) via a second lens group (8).
Claim 5
Dependent Claim
34 words
A system according to Claim 4 wherein said second lens group (8) incorporates a prism (9) to provide a desired turn in the optical path between the objective lens (1) and image intensifier (6).
Claim 6
Dependent Claim
20 words
A system according to Claim 5 wherein said second lens group (8) includes lenses before and after said prism (9).
Claim 7
Independent Claim
40 words
A system according to any one of Claims 2 to 6 wherein said light representing said intensified image passes to said eyepiece (3) from said fourth face (28) via a further lens group (4) and a reflecting mirror surface (15).
Claim 8
Independent Claim
51 words
A system according to any one of the preceding claims wherein said eyepiece (3) incorporates an internal curved surface (12) possessing both light transmitting and reflecting properties which serves as a collimating reflector for said light representing the intensified image and through which a user (14) views the forward scene (13).
Claim 9
Dependent Claim
100 words
A system according to Claim 8 wherein said internal curved surface (12) lies between flat parallel fore and aft faces (22, 21) of the eyepiece (3) through which the user (14) views the forward scene (13) , said curved surface (12) being concavely curved towards said aft face (21), said light representing said intensified image entering said eyepiece (3) via a face (30) between said fore and aft faces (22, 21), for internal reflection at said aft face (21) forwardly onto said curved surface (12) from which it is reflected rearwardly through said aft face (21) to the user (14).
Claim 10
Independent Claim
51 words
A system according to any one of Claims 2 to 9 wherein said second face (18) is partially reflective and the system includes means (7) for introducing light representing a further display into the prism means (2) via said second face (18) for combination with said light representing the intensified image.
Claim 11
Dependent Claim
30 words
A system according to Claim 10 wherein said light representing said further display passes to said second face (18) via an adjacent wedge portion (2C) of said prism means (2).
Claim 12
Dependent Claim
53 words
A system according to Claim 10 or Claim 11 wherein said light representing said further display passes to said prism means (2) via a further prism means (25) to provide a desired turn in the optical path between a source (19) of said light representing said further display and said second face (18).
Claim 13
Dependent Claim
20 words
A system according to Claim 12 including further lenses (26, 27) on either side of said further prism means (25).