Patent EP0360581A2 successfully refreshed from Google Patents.
EP0360581A2
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Optical system for a large depth-of-field bar code scanner
Assignee: HP Inc
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Filing: 1989-09-20
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Granted: —
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Expires: 2009-09-20
Abstract
Abstract An optical system for a bar code scanner has a working range (27,57,67) that is not determined by the lens aperture, but by the dimension and orientation of the detector (27,55). In the preferred embodiment, the desired working range (27,57,67) is imaged onto a detector array (25,51) using a modified Scheimpflug arrangement. The array (25,55) in the first Scheimpflug plane (B) with respect to the lens (21,41,61) defines a second Scheimpflug plane (C) that intersects the bar code tag (23,43,53) to be read. So long as the bar code tag (23,43,53) intersects the image (25a) of the detector array in (25,55) the second Scheimpflug plane (C) a portion of the image (23a) of the bar code tag (23,43,53) will be in focus on at least one of the elements of the detector array (25,55).
Inventors
- 👤 Brian J. Bayley
- 👤 Michael J. Brosnan
- 👤 Neil Hochgraf
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 12:09
CPC Classifications
G; G06; G06K; G06K7/00; G06K7/10; G06K7/10544; G06K7/10792; G06K7/10801; G06K7/10811; G06K7/10712; G06K7/10722; G06K2207/00; G06K2207/1013
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
108 words
An optical system for a bar code scanner for reading a bar code tag (23,43,53), characterised in that it comprises; focussing means (21,41,61) and detector means (25,55) positioned on a first surface (B) tilted with respect to the principal plane (A) of the focussing means (21,41,61) so that image (25a) of the detector means is formed on a second surface (C) intersecting the bar code tag (23,43,53) and an image (23a) of the bar code tag (23,43,53) is formed intersecting the first surface (B), with a portion of the image (23A) of the bar code tag (23,43,53) substantially in focus on at least part of the detector means.
Claim 2
Dependent Claim
108 words
An optical system for a bar code scanner for reading a bar code tag (23,43,53), characterised in that it comprises; focussing means (21,41,61) and detector means (25,55) positioned on a first surface (B) tilted with respect to the principal plane (A) of the focussing means (21,41,61) so that image (25a) of the detector means is formed on a second surface (C) intersecting the bar code tag (23,43,53) and an image (23a) of the bar code tag (23,43,53) is formed intersecting the first surface (B), with a portion of the image (23A) of the bar code tag (23,43,53) substantially in focus on at least part of the detector means.
Claim 3
Dependent Claim
21 words
An optical system according to claim 1, wherein the first and second surfaces (B,C) comprise first and second scheimpflug planes respectively.
Claim 4
Dependent Claim
19 words
An optical system according to claim 1 or 2, wherein the detector means (25,55) comprises a multi-element detector array.
Claim 5
Dependent Claim
23 words
An optical system according to any preceding claim, further comprising means for illuminating the bar code tag (23,43,53) along the second surface (C).
Claim 6
Dependent Claim
38 words
An optical system according to claim 3 or 4, wherein the detector elements (25,55) whose image is closest to the focussing means (21,41,61) are wider than the detector elements whose image is further away from the focussing means.
Claim 7
Dependent Claim
43 words
An optical system according to any of claims 3 to 5, wherein the detector array (25,55) extends beyond the focal point of the focussing means (21,41,61) so that the image (25a) of the detector array on the second surface (C) extends to infinity.
Claim 8
Dependent Claim
21 words
An optical system according to any of claims 3 to 6 wherein the detector array (65) is a two dimensional array.
Claim 9
Dependent Claim
68 words
An optical system according to claim 7, wherein the detector array (65) has columns of detector elements positioned along a line perpendicular to the intersection of the first surface (B) with the principal plane (A) of the focussing means (21,41,61) and rows of detector elements positioned along a line parallel to the intersection of the first surface (B) with the principal plane (A) of the focussing means (21,41,61).
Claim 10
Dependent Claim
67 words
An optical system according to any of claims 3 to 6, wherein the detector array (45) is a linear array positioned along a line perpendicular to the intersection of the first surface (B) with the principal plane (A) of the focussing means (21,41,61) and the optical system further comprises means (42) for scanning the image (25a) of the detector array (25,55) across the bar code tag (23,43,53).
Claim 11
Dependent Claim
35 words
An optical system according to any of claims 3 to 8, wherein the detector elements imaged closer to the optical system have larger areas than the detector elements imaged farther away from the optical system.
Claim 12
Dependent Claim
32 words
An optical system according to claim 9 or 10, wherein the scanning means (42) scans the image (25a) of the detector array (25,55) so that the working range (27,57,67) extends to infinity.
Claim 13
Dependent Claim
32 words
An optical system according to claim 9 or 10, wherein the scanning means physically moves the linear array (25,55) across the image of the working range (27.57,67) on the first surface (B).
References Cited (Backward Citations)
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