Patent US4938763B1 successfully refreshed from Google Patents.
EP0426248A2
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EP
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Grating objective and grating-beam shaper, and optical scanning device comprising at least one of said elements
Assignee: Koninklijke Philips NV
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Filing: 1990-10-29
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Granted: —
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Expires: 2010-10-29
Abstract
Abstract A grating objective is described which comprises at least three gratings and in which the axial ray and a border ray of a radiation beam are interchanged at least three times so that the objective has a wavelength-independent behaviour, a relatively large image field and a satisfactorily uniform intensity distribution. A beam shaper and a grating objective with a built-in beam shaper based on the same principle are also described.
Inventors
- 👤 Josephus Johannes Maria Braat
- 👤 Willem Gerard Opheij
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 04:41
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1372; G11B7/1374; G11B7/1353; G02; G02B; G02B13/00; G02B27/00; G02B27/0025; G02B27/0037; G02B27/42; G02B27/4233; G02B27/4238; G02B27/4272; G02B5/00; G02B5/18; G02B5/1814; G11B7/123
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
112 words
A grating objective comprising a first and a second diffraction grating which are arranged one behind the other in the radiation path extending from the object side to the image side, the gratings being adapted and arranged in such a way that a beam ray which is an axial ray or a border ray for one grating is a border ray or an axial ray, respectively, for the other grating, characterized by at least a third grating arranged in the radiation path formed by the first and the second grating, so that the axial ray and the border ray of a beam traversing the grating objective are interchanged at least three times.
Claim 2
Dependent Claim
112 words
A grating objective comprising a first and a second diffraction grating which are arranged one behind the other in the radiation path extending from the object side to the image side, the gratings being adapted and arranged in such a way that a beam ray which is an axial ray or a border ray for one grating is a border ray or an axial ray, respectively, for the other grating, characterized by at least a third grating arranged in the radiation path formed by the first and the second grating, so that the axial ray and the border ray of a beam traversing the grating objective are interchanged at least three times.
Claim 3
Dependent Claim
16 words
A grating objective as claimed in Claim 1, characterized in that all gratings are transmission gratings.
Claim 4
Dependent Claim
109 words
A grating objective as claimed in Claim 1, comprising a transparent plane-parallel plate having a first surface at the object side and a second surface at the image side and an optical axis perpendicular to the first and second surfaces, characterized in that the first surface has a radiation window surrounding the optical axis, in that a first grating is reflecting and is arranged on the second surface around the optical axis, in that a second grating is reflecting and is arranged around the radiation window on the first surface and in that a third grating is radiation-transmissive and is arranged on the second surface around the first grating.
Claim 5
Dependent Claim
71 words
A beam shaper for reshaping a beam having an elliptic cross-section to a beam having a circular-symmetrical cross-section, characterized by a system of at least three gratings which are arranged one behind the other in the path of the beam, the gratings being adapted in such a way that the axial ray and a border ray of the beam are interchanged at least three times, while the gratings are one-dimensional gratings.
Claim 6
Dependent Claim
71 words
A beam shaper for reshaping a beam having an elliptic cross-section to a beam having a circular-symmetrical cross-section, characterized by a system of at least three gratings which are arranged one behind the other in the path of the beam, the gratings being adapted in such a way that the axial ray and a border ray of the beam are interchanged at least three times, while the gratings are one-dimensional gratings.
Claim 7
Dependent Claim
16 words
A beam shaper as claimed in Claim 4, characterized in that all gratings are transmission gratings.
Claim 8
Dependent Claim
18 words
A beam shaper as claimed in Claim 4, characterized in that an even number of gratings is reflecting.
Claim 9
Dependent Claim
35 words
A grating objective as claimed in Claim 1, 2 or 3, comprising a built-in beam shaper, characterized in that it comprises two-dimensional gratings each having grating periods which are different in two mutually perpendicular directions.
Claim 10
Dependent Claim
55 words
A device for optically scanning an information plane, which device comprises a radiation source supplying a scanning beam and an objective system for focusing the scanning beam to a radiation spot in the information plane, characterized in that the objective system is constituted by a grating objective as claimed in Claim 1, 2 or 3.
Claim 11
Dependent Claim
64 words
A device for optically scanning an information plane, which device comprises a radiation source supplying a scanning beam having an elliptic cross-section, a beam shaper for reshaping the elliptic beam cross-section to a circular cross-section and an objective system for focusing the scanning beam to a scanning spot in the information plane, characterized by a beam shaper as claimed in Claim 4, or 6.
Claim 12
Dependent Claim
67 words
A device for optically scanning an information plane, which device comprises a radiation source supplying a scanning beam having an elliptic cross-section, a beam shaper for reshaping the elliptic beam cross-section to a circular cross-section and an objective system for focusing the scanning beam to a scanning spot in the information plane, characterized by a grating objective comprising a built-in beam shaper as claimed in Claim 7.
Claim 13
Dependent Claim
39 words
A device as claimed in Claim 8 or 10, characterized in that an entrance window of the grating objective is provided with a coupling-out grating for diverting radiation returning through the objective from the path of the source radiation.
Claim 14
Dependent Claim
30 words
A device as claimed in Claim 8, 10 or 11, characterized in that the grating objective and the radiation-sensitive detection system are arranged in the housing of the radiation source.
References Cited (Backward Citations)
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