Method and apparatus for inspecting a surface
First Claim
1. A method of inspecting a curved surface on an article, said method comprising the steps of impinging beams of light in a predetermined order against each point in an arcuate series of points on a stationary curved surface by projecting the beams of light in a predetermined order along a plurality of parallel first paths which are offset in a first direction by a known distance, reflecting light beams from each of the points in the series of points in turn along second paths which are offset in the first direction by an amount corresponding to the distance which the first paths are offset in the first direction and which are offset in a second direction transverse to the first direction by an amount corresponding to the distance which the points in the series of points are offset due to curvature of the surface of the article, and eliminating the offset in the first direction between the reflected light beams and maintaining the offset in the second direction between the reflected light beams by sequentially focusing the reflected light beams on a linear detector with the distance between locations at which the reflected light beams are focused on the linear detector corresponding to the distance which the points on the surface in the series of points are offset due to curvature of the surface of the article.
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Accused Products
Abstract
An improved method and apparatus for inspecting the curved surface of a stationary article includes a mirror which is moved to direct a beam of light from a light source through a lens against each point of an arcuate series of points on a curved surface of the article. A second lens focuses beams of light reflected from the article onto a linear detector. The distance between locations at which the reflected light beams are focused on the linear detector corresponds to the distance at which points on the surface of the article are offset due to the curvature of the surface of the article.
215 Citations
9 Claims
- 1. A method of inspecting a curved surface on an article, said method comprising the steps of impinging beams of light in a predetermined order against each point in an arcuate series of points on a stationary curved surface by projecting the beams of light in a predetermined order along a plurality of parallel first paths which are offset in a first direction by a known distance, reflecting light beams from each of the points in the series of points in turn along second paths which are offset in the first direction by an amount corresponding to the distance which the first paths are offset in the first direction and which are offset in a second direction transverse to the first direction by an amount corresponding to the distance which the points in the series of points are offset due to curvature of the surface of the article, and eliminating the offset in the first direction between the reflected light beams and maintaining the offset in the second direction between the reflected light beams by sequentially focusing the reflected light beams on a linear detector with the distance between locations at which the reflected light beams are focused on the linear detector corresponding to the distance which the points on the surface in the series of points are offset due to curvature of the surface of the article.
- 3. A method of inspecting a curved surface on an article, said method comprising the steps of locating the article with respect to a reference plane having first and second intersecting axes therein such that the curved surface is referenced with respect to a third axis extending through the point of intersection of said intersecting axes, forming beams of light each offset in a common plane and directly impinging such beams without reflection in a predetermined order against each point in a series of points on the curved surface while the surface remains stationary, reflecting light beams from each of the points on the stationary curved surface to form reflected beams offset with respect to each other and to the third axis, focusing the reflected light beams along a straight line on a stationary linear detector, and maintaining the same spatial orientation between the curved surface and the linear detector during performance of the aforementioned method steps.
- 6. An apparatus for use in inspecting the curved surface of a stationary article, said apparatus comprising means for directing beams of light each offset in a common plane and in a known order against each point of a series of points on the curved surface of the article, linear detector means for detecting the presence of beams of light which impinge against said linear detector means along a straight line, means for focusing on said linear detector means beams of light reflected from the points in the series of points on the curved surface wherein said reflected beams are offset with respect to each other and to an axis in the common plane, means for holding said curved surface stationary during the directing of beams of light against each point in the series of points on the curved surface, and means for holding said linear detector means stationary during the focusing of beams of light on said linear detector means.
Specification