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EP0584769A2
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Two-dimensional optical low-pass filter
Assignee: Panasonic Holdings Corp
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Filing: 1993-08-24
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Granted: —
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Expires: 2013-08-24
Abstract
Abstract A two-dimensional optical low-pass filter includes an optical phase grating having a plurality of unitary grating periods (G) only on one side of a grating plane (1). Each of the unitary grating periods (G) includes at least two phase retardation structures (2, 2a, 2b; 4) spaced from each other, thereby providing phase retardation across the grating plane (1). The two phase retardation structures (2, 2a, 2b; 4) invariably have at least one non-continuous phase retardation configuration substantially in all directions on the grating plane (1).
Inventors
- 👤 Hiroaki Okayama
- 👤 Shusuke Ono
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 14:44
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/18; G02B5/1866; G02B5/1871; G02B27/00; G02B27/42; G02B27/46
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
58 words
A two-dimensional optical low-pass filter comprising: an optical phase grating having a plurality of unitary grating periods (G) only on one side of a grating plane (1), each of said unitary grating periods (G) including at least two phase retardation structures (2, 2a, 2b; 4) spaced from each other, thereby providing phase retardation across the grating plane (1).
Claim 2
Dependent Claim
38 words
The optical low-pass filter according to claim 1, wherein said at least two phase retardation structures (2, 2a, 2b; 4) invariably have at least one non-continuous phase retardation configuration substantially in all directions on the grating plane (1).
Claim 3
Dependent Claim
137 words
A two-dimensional optical low-pass filter comprising: an optical phase grating having a plurality of rectangular unitary grating periods (G) only on one side of a grating plane (1); a plurality of first phase retardation elements (2, 2a, 2b) formed in a two-dimensional matrix on said one side of the grating plane (1); a plurality of second phase retardation elements (4) regularly spaced from said first phase retardation elements (2, 2a, 2b), each of said first phase retardation elements (2, 2a, 2b) being surrounded by four second phase retardation elements (4); and each of said unitary grating periods (G) including one first phase retardation element (2, 2a, 2b) at a center thereof and a quarter of each of four surrounding second phase retardation elements (4) at each corner thereof, thereby providing phase retardation across the grating plane (1).
Claim 4
Dependent Claim
38 words
The optical low-pass filter according to claim 3, wherein each of said first phase retardation elements (2, 2a, 2b) has a generally cross-shaped base and each of said second phase retardation elements (4) has a generally rectangular base.
Claim 5
Dependent Claim
159 words
An image pickup element comprising: an image plane (19); and a two-dimensional optical low-pass filter (17) spaced from said image plane (19), said optical low-pass filter (17) comprising: an optical phase grating having a plurality of rectangular unitary grating periods (G) only on one side of a grating plane (1); a plurality of first phase retardation elements (2, 2a, 2b) formed in a two-dimensional matrix on said one side of the grating plane (1); a plurality of second phase retardation elements (4) regularly spaced from said first phase retardation elements (2, 2a, 2b), each of said first phase retardation elements (2, 2a, 2b) being surrounded by four second phase retardation elements (4); and each of said unitary grating periods (G) including one first phase retardation element (2, 2a, 2b) at a center thereof and a quarter of each of four surrounding second phase retardation elements (4) at each corner thereof, thereby providing phase retardation across the grating plane (1).
Claim 6
Dependent Claim
38 words
The image pickup element according to claim 5, wherein each of said first phase retardation elements (2, 2a, 2b) has a generally cross-shaped base and each of said second phase retardation elements (4) has a generally rectangular base.
References Cited (Backward Citations)
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