EP0584769B1
Expired / Lapsed
EP
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Two-dimensional optical low-pass filter
Assignee: Panasonic Holdings Corp
•
Filing: 1993-08-24
•
Granted: 1998-01-28
•
Expires: 2013-08-24
Abstract
No abstract record available.
Inventors
- 👤 Hiroaki Okayama
- 👤 Shusuke Ono
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 05:59
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/18; G02B5/1866; G02B5/1871; G02B27/00; G02B27/42; G02B27/46
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
129 words
A two-dimensional optical low-pass filter, comprising: a generally planar substrate (1) having two opposite surfaces; and an optical phase
grating comprising a plurality of unitary structural units on only one surface of said
substrate (1), each one of said plurality of unitary structural units comprising at
least two different phase retardation structures (2, 2a, 2b; 4) spaced from each
other on said one surface of said substrate (1); wherein said at least two different
phase retardation structures (2, 2a, 2b; 4) in each one of said plurality of unitary
structural units are arranged with no continuous space along any direction in a
plane parallel to said one surface of said substrate (1) to provide a phase retardation
across said substrate (1) which varies along any direction in said plane.
Claim 2
Dependent Claim
211 words
The two-dimensional optical low-pass filter according to claim 1, wherein
each of said unitary structural units is of a rectangular shape having a center and
four corners, wherein said plurality of unitary structural units comprise a plurality
of first phase retardation elements (2, 2a, 2b) formed in a two-dimensional matrix
and 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 of said second phase retardation
elements (4), wherein each one of said plurality of unitary structural units comprises
one of said first phase retardation elements (2, 2a, 2b) at said center thereof
and a quarter of each of the respective said four of said second phase retardation
elements (4) surrounding the one of said first phase retardation elements (2, 2a,
2b), each said quarter being located at a respective one of said four corners of said
unitary structural unit, and wherein said first and second phase retardation
structures in each one of said plurality of unitary structural units are arranged with
no continuous space along any direction in said plane to provide a phase retardation
across said substrate (1) which varies along any direction in said plane.
Claim 3
Dependent Claim
37 words
The two-dimensional optical low-pass filter according to claim 2, wherein
each of said first phase retardation elements (2) has a substantially cross-shaped
base and each of said second phase retardation elements (4) has a substantially
rectangular base.
Claim 4
Dependent Claim
34 words
The two-dimensional optical low-pass filter according to claim 3, wherein
each of said first phase retardation elements (2, 2a, 2b) has a recess (6, 6a, 6b)
in the center of said substantially cross-shaped base.
Claim 5
Dependent Claim
27 words
An image pickup element comprising a two-dimensional optical low-pass
filter (17) according to claim 2 and an image plane element (19) spaced from said
low-pass filter (17).
Claim 6
Dependent Claim
37 words
The image pickup element according to claim 5, wherein each of said first
phase retardation elements (2, 2a, 2b) has a substantially cross-shaped base and
each of said second phase retardation elements (4) has substantially rectangular
base.
Claim 7
Dependent Claim
30 words
The image pickup element according to claim 6, wherein each of said first
phase retardation elements has a recess (6, 6a, 6b) in the center of said substantially
cross-shaped base.
References Cited (Backward Citations)
No citation records indexed.
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