Optics: measuring and testing – Angle measuring or angular axial alignment – Photodetection of inclination from level or vertical
Reexamination Certificate
1999-11-02
2001-11-20
Buczinski, Stephen C. (Department: 3662)
Optics: measuring and testing
Angle measuring or angular axial alignment
Photodetection of inclination from level or vertical
C033S366120, C033S366160, C033S366230
Reexamination Certificate
active
06320653
ABSTRACT:
BACKGROUND OF THE INVENTION
a) Field of the Invention
The invention is directed to a multiple-axis inclinometer for measuring inclinations and changes in inclination, especially for precision measurements with geodetic devices.
b) Description of the Related Art
Devices with a cuvette or cell with a liquid forming a horizon are used for precise measurements of inclination. A projected light bundle is reflected at this liquid horizon.
Conventional biaxial inclinometers have a prism with a cell and separate optics which serve to image a pattern of cross-lines on a CCD line via a liquid horizon on the transmitter side or via a surface sensor on the receiver side. An imaging system and a measurement system which are arranged perpendicular to one another are provided for each direction of inclination. In this respect, it is difficult to accommodate the four optical systems of the crossed imaging systems in a very compact space.
These difficulties are overcome by a biaxial inclinometer according to DE 198 19 6510 which is constructed in a very simple manner. A thick plano-convex lens at the base of a liquid cell takes over the function of illumination optics as well as imaging optics for cross-line patterns which are imaged on a CCD line. Corresponding measurement values are determined for the inclinations by displacing the images of the cross-line patterns on the CCD lines.
DE 41 10 858 describes a biaxial inclinometer which has an imaging system and a cross-line pattern which has cross-lines arranged at right angles to one another and is illuminated by a light source in the transmitter plane. This cross-line figure has at least one angle whose imaged side intersects a CCD line at two points. Measurement values for determining the transverse and longitudinal inclination of the device can be derived from the change in distance or from the simultaneous common displacement of these two points occurring when the device is inclined and corresponding inclination values are determined from these measurement values. This inclinometer does not need intersecting illumination and imaging systems for the cross-line pattern. However, it is disadvantageous that only inclinations in a small angular range can be measured. Also, the arrangement of illumination optics and imaging optics has a negative effect on the size of the inclinometer in that there can be no reduction below certain boundary magnitudes.
OBJECT AND SUMMARY OF THE INVENTION
It is the primary object of the invention to provide a multiple-axis inclinometer having compact dimensions, enabling highly precise measurements of inclination and requiring fewer components.
This object is met according to the invention in a multiple-axis inclinometer for measuring inclinations and changes in inclination comprises a cell which contains a liquid forming a horizon and which has a transparent base, and a device for illuminating a cross-line plate and imaging optics in the form of a plano-convex lens, which is arranged at the base of the cell or is a component part of the base, for imaging the cross-line plate on a receiver arrangement in the form of a CCD line. Two cross-line plates are provided, each having a cross-line grid formed of parallel cross-lines, wherein a light source is associated with each cross-line plate and illuminates the cross-line plate associated therewith. These two cross-line plates lie one above the other in an imaging plane which extends perpendicular to the surface of the liquid and in which the CCD line is also arranged, wherein the cross-lines of the two cross-line plates enclose an angle relative to one another whose bisector extends perpendicular to the imaging plane. The imaging of the two cross-line grids located at a distance from one another is carried out on the CCD line by means of total reflection at the horizon of the liquid and through the plano-convex lens.
Accordingly, the cell, the imaging optics and the CCD line are rigidly connected with one another to form a unit. The cross-lines of each graticule or cross-line plate run parallel to one another and are equidistant or at different distances from one another. The cross-line thicknesses can be identical or different.
An advantageous arrangement of the two cross-line plates relative to one another is given when the cross-lines of both cross-line plates form an angle of 90° and the cross-lines of every cross-line plate itself form an angle of 45° with the imaging plane.
Further, it can be advantageous when the two cross-line plates are combined to form one plate, wherein the two cross-line grids of the arrangement shown herein lie in different cross-line fields located at a distance from one another and these cross-line fields are illuminated separately or jointly in a corresponding manner by one light source for each or by a common light source.
The multiple-axis inclinometer according to the invention for the measurement of inclinations and changes in inclination is characterized by a high sensitivity and a large measurement range, so that highly precise measurements can be carried out with it. Due to the simplicity of the construction, it is possible to make do with a few simple components for the construction.
The invention will be described more fully in the following with reference to an embodiment example.
REFERENCES:
patent: 4666299 (1987-05-01), Tamaki et al.
patent: 5371951 (1994-12-01), Piske
patent: 5392112 (1995-02-01), Nakamura
patent: 5510892 (1996-04-01), Mizutani et al.
patent: 5729337 (1998-03-01), Tanaka
patent: 677403 (1991-05-01), None
patent: 41 10 858 (1991-04-01), None
patent: 196 10 941 (1997-09-01), None
patent: 198 19 610 (1999-08-01), None
English Abstract of CH 677,403.
English Abstract of DE 198 19 610.
English Abstract of DE 196 10 941.
English Abstract of DE 41 10 858.
Buczinski Stephen C.
Carl Zeiss Jena GmbH
Reed Smith LLP
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