US5106183A — Topography measuring apparatus

Claim 1

Independent Claim 188 words

A contour measuring apparatus to measure the three-dimensional contour of a surface, comprising: a multi-point light source to direct a plurality of individual light beams each corresponding to individual light points of the multi-point light source onto the surface being measured; a photodetector receiving reflections of the individual light beams from the measured surface for generating electrical output signals corresponding to electro-optically measurable optical images, each of said images corresponding to one of said light points; means disposed between said surface being measured and said photodetector for focusing the reflected beams of light from the surface being measured onto the photodetector to form the measurable optical images; means between the focusing means and said photodetector for controlling the size of the area on the measured surface from which the beams of light are reflected; means receiving said electrical output signals from said photodetector for measuring the position of each optical image in the photodetector and for determining both the local radius of curvature of the measured surface at each point of incidence of the individual corresponding light beams and the average radius of curvature of the measured surface.

Claim 2

Dependent Claim 188 words

A contour measuring apparatus to measure the three-dimensional contour of a surface, comprising: a multi-point light source to direct a plurality of individual light beams each corresponding to individual light points of the multi-point light source onto the surface being measured; a photodetector receiving reflections of the individual light beams from the measured surface for generating electrical output signals corresponding to electro-optically measurable optical images, each of said images corresponding to one of said light points; means disposed between said surface being measured and said photodetector for focusing the reflected beams of light from the surface being measured onto the photodetector to form the measurable optical images; means between the focusing means and said photodetector for controlling the size of the area on the measured surface from which the beams of light are reflected; means receiving said electrical output signals from said photodetector for measuring the position of each optical image in the photodetector and for determining both the local radius of curvature of the measured surface at each point of incidence of the individual corresponding light beams and the average radius of curvature of the measured surface.

Claim 3

Dependent Claim 55 words

The contour measuring apparatus of claim 1 wherein said means for controlling the size of the area further comprises means for limiting the cone angle of the rays of the individual light beams reflected from the measured surface whereby each of said reflected rays closely approximates a telecentric principal ray corresponding to a light point.

Claim 4

Dependent Claim 31 words

The contour measuring apparatus of claim 2 wherein said means for controlling the size of the area comprises a telecentric aperture stop having an effective aperture of no larger than f/13.

Claim 5

Dependent Claim 27 words

The apparatus of claim 3 in which said telecentric aperture stop is positioned between said lens and said photodetector substantially at the focal point of said lens.

Claim 6

Dependent Claim 43 words

The apparatus of claim 4 wherein the focusing means comprises a lens having and optical axis extending therethrough; and said photodetector includes a photodetector surface into which said reflected light beams are focused, said photodetector surface being disposed transverse to said optical axis.

Claim 7

Dependent Claim 26 words

The apparatus of claim 5 further including means to determine and store in memory the location of each individual light point on said multi-point light source.

Claim 8

Dependent Claim 16 words

The apparatus of claim 6 wherein said means to determine and store include a frame grabber.

Claim 9

Dependent Claim 25 words

The apparatus of claim 7 wherein said means to determine both the local radius of curvature and the average radius of curvature comprises a computer.

Claim 10

Independent Claim 152 words

The method of measuring the three-dimensional contour of a surface, comprising the steps of: directing a plurality of individual light beams each corresponding to individual light points of a multi-point light source onto the surface being measured; reflecting the individual light beams from the measured surface onto a photodetector for generating electrical output signals corresponding to electro-optically measurable optical images, each of said images corresponding to one of said light points; focusing the reflected beams of light from the surface being measured onto the photodetector to form the measurable optical images; controlling the size of the area on the measured surface from which the beams of light are reflected; measuring the position of each optical image in the photodetector; and determining both the local radius of curvature of the measured surface at each point of incidence of the individual corresponding light beams and the average radius of curvature of the measured surface.

Claim 11

Independent Claim 152 words

The method of measuring the three-dimensional contour of a surface, comprising the steps of: directing a plurality of individual light beams each corresponding to individual light points of a multi-point light source onto the surface being measured; reflecting the individual light beams from the measured surface onto a photodetector for generating electrical output signals corresponding to electro-optically measurable optical images, each of said images corresponding to one of said light points; focusing the reflected beams of light from the surface being measured onto the photodetector to form the measurable optical images; controlling the size of the area on the measured surface from which the beams of light are reflected; measuring the position of each optical image in the photodetector; and determining both the local radius of curvature of the measured surface at each point of incidence of the individual corresponding light beams and the average radius of curvature of the measured surface.

Claim 12

Dependent Claim 54 words

The method of claim 9 wherein the step of controlling the size of the area further includes the step of limiting the cone angle of the rays of the individual light beams reflected from the measured surface whereby each of said reflected rays closely approximates a telecentric principal ray corresponding to a light point.

Claim 13

Dependent Claim 40 words

The method of claim 10 wherein the step of controlling the size further includes the step of directing the reflected rays of the individual light beams through a telecentric aperture stop having an effective aperture of no larger than f/13.

Claim 14

Independent Claim 297 words

The method of measuring the local radii of curvature (R 1 ) 1 and optical powers (P 1 ) 1 at i points with coordinates (X 1 , Y 1 ) 1 of a three-dimensional contour on a surface being measured, including the steps of: locating the center of curvature of the surface substantially on the optical axis of a contour measuring apparatus; directing a plurality of individual light beams, each corresponding to individual light points of a multi-point light source on a concave, substantially spherical surface onto the convex surface being measured; receiving reflections of the individual light beams from said surface on a photodetector; generating electrical output signals corresponding to positional relationships of optical images of said light points; determining the radial distances (Y 1 ) 1 from said optical axis to each of the i images of the array of i light points located at points with known coordinates (X 2 ,Y 2 ) 1 on the concave, substantially spherical surface of radius R 2 centered on said optical axis and located at a known distance d 1 measured along the optical axis in front of the convex surface; measuring the (X 1 ) 1 coordinates for these same i images from the equation: ##EQU5## where: A=(Y 1 ) 1 -(Y 2 ) 1 B=(X 2 ) 1 -(X 1 ) 1 D=A[2(Y 1 ) 1 -A] E=2A[AX c -X c (Y 2 ) 1 -(X 2 ) 1 (Y 1 ) 1 ] G=A 2 [(Y 1 ) 1 2 -X c 2 ]+2AX c X 2 Y 1 X c =d 1 +(R 1 ) 1' (R 1 ) 1' =assumed approximate value for this parameter; and measuring by successive approximations, the local radius (R 1 ) 1 from the equation: ##EQU6##

Claim 15

Independent Claim 297 words

The method of measuring the local radii of curvature (R 1 ) 1 and optical powers (P 1 ) 1 at i points with coordinates (X 1 , Y 1 ) 1 of a three-dimensional contour on a surface being measured, including the steps of: locating the center of curvature of the surface substantially on the optical axis of a contour measuring apparatus; directing a plurality of individual light beams, each corresponding to individual light points of a multi-point light source on a concave, substantially spherical surface onto the convex surface being measured; receiving reflections of the individual light beams from said surface on a photodetector; generating electrical output signals corresponding to positional relationships of optical images of said light points; determining the radial distances (Y 1 ) 1 from said optical axis to each of the i images of the array of i light points located at points with known coordinates (X 2 ,Y 2 ) 1 on the concave, substantially spherical surface of radius R 2 centered on said optical axis and located at a known distance d 1 measured along the optical axis in front of the convex surface; measuring the (X 1 ) 1 coordinates for these same i images from the equation: ##EQU5## where: A=(Y 1 ) 1 -(Y 2 ) 1 B=(X 2 ) 1 -(X 1 ) 1 D=A[2(Y 1 ) 1 -A] E=2A[AX c -X c (Y 2 ) 1 -(X 2 ) 1 (Y 1 ) 1 ] G=A 2 [(Y 1 ) 1 2 -X c 2 ]+2AX c X 2 Y 1 X c =d 1 +(R 1 ) 1' (R 1 ) 1' =assumed approximate value for this parameter; and measuring by successive approximations, the local radius (R 1 ) 1 from the equation: ##EQU6##

Claim 16

Dependent Claim 43 words

The method of claim 12 including the step of measuring by successive approximations, the local optical power (P 1 ) 1 (in diopters) from the equation: (P.sub.1).sub.1 =1000(N-1)/(R.sub.1).sub.1 where: N=index of refraction of the material on which the surface under evaluation is located.

Claim 17

Dependent Claim 58 words

The method of claim 12 further including the step of limiting the cone angle of the rays within the individual light beams reflected from the convex surface to be measured whereby these rays closely approximate a telecentric principal ray corresponding to an individual light point and limit the area intercepted on said surface to a small localized area.

Claim 18

Dependent Claim 26 words

The method of claim 13 further including the step of focusing the reflected light beams from said surface onto the photodetector to form measurable optical images.

Claim 19

Dependent Claim 21 words

The method of claim 15 further including the step of measuring the position of each optical image formed on the photodetector.

Claim 20

Dependent Claim 142 words

The method of measuring the coordinates (X 2 ) 1 , (Y) 1 of each light point of the contour measuring apparatus of claim 12, including the steps of: substituting a generally spherical calibration surface of known radius of curvature R 2 in lieu of the surface being measured; measuring the radial distances (Y 1 ) 1 from the optical axis to each of the i images of said array of i point light points using the following equations: K.sub.1 =(X.sub.c -X.sub.1)Y.sub.1.sup.2 K.sub.2 =(X.sub.1 -X.sub.c)Y.sub.1 K.sub.3 =Y.sub.1.sup.2 -X.sub.c.sup.2 +2X.sub.c X.sub.1 -X.sub.1.sup.2 K.sub.4 =2(X.sub.c.sup.2 Y.sub.1 -X.sub.c X.sub.1 Y.sub.1 -Y.sub.1.sup.3) K.sub.5 =Y.sub.1.sup.4 +X.sub.1.sup.2 Y.sub.1.sup.2 -X.sub.c C.sup.2 Y.sub.1.sup.2 H=4K.sub.2.sup.2 +K.sub.3.sup.2 I=(4K.sub.2 K.sub.3 R.sub.2 +2K.sub.3 K.sub.4 +8K.sub.1 K.sub.2)/H J=(4K.sub.1.sup.2 +4K.sub.1 K.sub.3 R.sub.2 +4K.sub.2 K.sub.4 R.sub.2 +2K.sub.3 K.sub.5 +K.sub.4.sup.2)/H L=(4K.sub.1 K.sub.4 R.sub.2 +4K.sub.2 K.sub.5 R.sub.2 +2K.sub.4 K.sub.5)/H M=(4K.sub.1 K.sub.5 R.sub.2 +K.sub.5.sup.2)/H Y.sub.2.sup.4 +IY.sub.2.sup.3 +JY.sub.2.sup.2 +LY.sub.2 +M=0 ##EQU7##

Claim 21

Independent Claim 128 words

An apparatus to measure the three-dimensional contour of a surface, comprising: a contour measuring device having an optical axis extending therethrough, said contour measuring device comprising: means to direct light beams onto the surface being measured; means for receiving reflections of said light beams from the surface being measured; means connected to the reflection receiving means for measuring the contour of said surface; means for positioning the surface being measured with respect to the reflection receiving means to establish a desired axial distance therebetween; said means for positioning comprising an optical microscope attached to said contour measuring device so that a line of sight extending outwardly from said optical microscope is perpendicular to the axis through said contour measuring device and substantially tangent to the surface being measured.

Claim 22

Independent Claim 128 words

An apparatus to measure the three-dimensional contour of a surface, comprising: a contour measuring device having an optical axis extending therethrough, said contour measuring device comprising: means to direct light beams onto the surface being measured; means for receiving reflections of said light beams from the surface being measured; means connected to the reflection receiving means for measuring the contour of said surface; means for positioning the surface being measured with respect to the reflection receiving means to establish a desired axial distance therebetween; said means for positioning comprising an optical microscope attached to said contour measuring device so that a line of sight extending outwardly from said optical microscope is perpendicular to the axis through said contour measuring device and substantially tangent to the surface being measured.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1995-04-21	1995-10-21	1996-04-21	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1999-04-21	1999-10-21	2000-04-21	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2003-04-21	2003-10-21	2004-04-21	$7700.00	Window Closed / Lapsed

Topography measuring apparatus

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