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EP0010241A2
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Distance sensing apparatus
Assignee: Erwin Sick GmbH Optik Elektronik
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Filing: 1979-10-06
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Granted: —
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Expires: 1999-10-06
Abstract
Abstract Distance sensing apparatus for determining the distance to an illuminated surface features an objective, forforming an image of the illuminated surface, and first and second photo- electric converters respectively disposed at first and second image planes respectively corresponding to first and second object planes equivalent to maximum and minimum possible distances of the illuminated surface from the apparatus. The arrangement is such that the light falling on the first and second photo-electric converters depends on the location of the illuminated surface between the maximum and minimum possible distances. Electronic processing circuitry is able to uniquely define this location from the outputs of the two photoelectric converters. The illuminated surface is preferably illuminated from a light source contained within the distance sensing apparatus and which uses the central portion of the objective lens to form a parallel illuminating beam. A mirror can conveniently be positioned between the first and second image planes to increase the effective distance therebetween, which results in a more compact construction. The processing circuitry conveniently includes either a difference forming stage or a quo- tientforming stage which respectively enable either a qualitative or quantitative determination of the location of the illuminated surface.
Inventors
- 👤 Jürgen Erdmann
- 👤 Günter Fetzer
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 17:19
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/30; G02B7/32; G01; G01C; G01C3/00; G01C3/02; G01C3/06; G01C3/08
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
152 words
Distance sensing apparatus (28) for determining the distance of an illuminated surface (27) from the apparatus,said apparatus comprising lens means (20 for forming an image of said illuminated surface and photoelectric detection means the apparatus being characterized by first and second photoelectric converters (14, 15) respectively disposed at first and second image planes (11', 12') of said lens means, said first and second image planes (11', 12') respectively corresponding to first and second object planes (11, 12) equivalent to near and remote possible locations of said illuminated surface from the apparatus, whereby the light falling on the first and second photoelectric converters (14, 15) depends on the location of the illuminated surface, and by processing means (16, 17) for processing the output signals from said first and second photoelectric converters (14, 15) to produce a single output signal (17) representative of the distance of said illuminated surface (27) from the apparatus (28).
Claim 2
Dependent Claim
152 words
Distance sensing apparatus (28) for determining the distance of an illuminated surface (27) from the apparatus,said apparatus comprising lens means (20 for forming an image of said illuminated surface and photoelectric detection means the apparatus being characterized by first and second photoelectric converters (14, 15) respectively disposed at first and second image planes (11', 12') of said lens means, said first and second image planes (11', 12') respectively corresponding to first and second object planes (11, 12) equivalent to near and remote possible locations of said illuminated surface from the apparatus, whereby the light falling on the first and second photoelectric converters (14, 15) depends on the location of the illuminated surface, and by processing means (16, 17) for processing the output signals from said first and second photoelectric converters (14, 15) to produce a single output signal (17) representative of the distance of said illuminated surface (27) from the apparatus (28).
Claim 3
Dependent Claim
36 words
Distance sensing apparatus in accordance with claim 1 and characterized in that said near and remote locations correspond to maximum and minimum possible distances (11, 12) for the position of said illuminated surface from the apparatus.
Claim 4
Dependent Claim
65 words
Distance sensing apparatus in accordance with either of the preceding claims and characterized in that said processing means (16, 17) comprises a difference forming stage (18) for producing a signal representative of the difference between the outputs of said first and second photoelectric detectors (14, 15) and a display device (17) (Fig. 3) connected to said difference forming stage (16) for displaying said difference signal.
Claim 5
Dependent Claim
33 words
Distance sensing apparatus in accordance with any preceding claim and characterized in that the display device (17) (Fig. 3) solely indicates whether the difference signal is zero or smaller or larger than zero.
Claim 6
Dependent Claim
61 words
Distance sensing apparatus in accordance with either of claims 1 or 2 and characterized in that said processing circuit (16, 17) comprises a quotient forming stage (19) for forming a quotient signal representative of the quotients of the outputs of said first and second photo- electric converters (14, 15) and a display device (17) (Fig. 4) for displaying said quotient signal.
Claim 7
Dependent Claim
36 words
A distance sensing apparatus according to claim 5 and characterized in that the quotient signal display device (17) (Fig. 4) is calibrated to show the location of the illuminated surface with reference to a reference plane.
Claim 8
Dependent Claim
23 words
Distance sensing apparatus in accordance with any one of the preceding claims and characterized in that said lens means (20) comprises an objective.
Claim 9
Dependent Claim
40 words
Distance sensing apparatus in accordance with any one of the preceding claims and characterized in that there is further provided a central aperture stop (22) for restricting the usable aperture of said lens means (20) to a marginal region thereof.
Claim 10
Dependent Claim
27 words
Distance sensing apparatus in accordance with claim 8 and characterized in that said aperture stop (22) is arranged on the image side of said lens means (20).
Claim 11
Dependent Claim
62 words
Distance sensing apparatus in accordance with claim 9 and characterized in that said aperture stop (20) is at a distance ("a") from said lens means so that said first and second photoelectric converters receive substantially the same quantities of light from their associated first and second object planes when the same surface with the same illumination is located at those object planes.
Claim 12
Dependent Claim
92 words
Distance sensing apparatus in accordance with any one of the preceding claims and characterized in that the one (12') of said first and second image planes (11', 12') which lies closest to the lens means (20) is moved towards.the lens means (20) by means of a mirror (21) sized and positioned so as not to interrupt the ray path to the other (11') of said first and second image planes (11', 12') when said illuminated surface is located at the corresponding one (11.) of said first and second object planes (11, 12).
Claim 13
Dependent Claim
19 words
Distance sensing apparatus in accordance with claim 11 and characterized in that said mirror (21) comprises a plane mirror.
Claim 14
Dependent Claim
38 words
Distance sensing apparatus according to any one of claims 8 to 12 and characterized in that said aperture stop (22) is provided with a central opening (23) and a light source (25) is arranged behind said central opening.
Claim 15
Dependent Claim
49 words
Distance sensing apparatus in accordance with claim 13 and characterized in that a further lens (24) is located within said central opening and cooperates with said lens means (20). to form the light (26) leaving said light source (25) into a parallel light beam for illuminating said surface (27).
Claim 16
Dependent Claim
38 words
Distance sensing apparatus in accordance with any one of the preceding claims and characterized in that at least one of said first and second photoelectric converters(14, 15) is disposed on the optical axis (13) of said lens (20).
References Cited (Backward Citations)
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