System and method for non-contact metrology of surfaces

A non-contact metrology system comprising:

• a programmable display screen that is programmed to display a pattern of targets such that when the screen is placed a known distance in front of a specular surface, the display screen will produce an array pattern of images reflected from the surface;
• an imaging device located proximate the display screen and focused on the surface, the imaging device configured to generate an output image to thereby provide slope information in two orthogonal directions based on a single output image;
• and
• a computing device configured to calculate the slopes of the surface and to integrate the slopes to give the surface topography.

A non-contact metrology system comprising:

• a programmable display screen, placed at a known location in front of a specular surface, that is programmed to display a pattern of targets one target at a time in two orthogonal directions and to move each target so that its reflection from the surface forms an evenly spaced grid;
• an imaging device located proximate the display screen and focused on the surface, the imaging device configured to generate an output image to thereby provide slope information;
• and
• a computing device configured to calculate the slopes of the surface and to integrate the slopes to give the surface topography.

A non-contact metrology system comprising:

• a programmable display screen that is programmed to display a pattern of targets such that, when the screen is placed a known distance in front of a refracting lens or optical system, the screen will produce an array pattern of rays refracted in the lens or optical system;
• an imaging device located a known distance from the lens or optical system and focused on the lens or optical system, the imaging device generating an output image to thereby provide slope information;
• and
• a computing device configured to calculate the slopes of the rays produced by the lens and to integrate the slopes to give the shape of the wavefront emanating from the lens or optical system.

A non-contact metrology method to measure a surface, comprising:

• positioning a display proximate a first side of the surface to be measured;
• generating a pattern for display on the display, the pattern having a plurality of targets in two dimensions with each of the plurality of targets being separated from others of the plurality of targets in two dimensions;
• generating an image of at least a portion of the plurality of targets after interaction with the surface;
• and
• analyzing the image to determine if the plurality of targets in the image are in expected locations following interaction with the surface wherein generating a pattern for display on the display comprises generating the plurality of targets in an irregularly-spaced display pattern and the expected locations are in a regularly-spaced display pattern following interaction with the surface.

A non-contact metrology system to measure a surface having an optical axis, comprising:

• a display positioned proximate a first side of the surface to be measured;
• a pattern generator configured to generate a pattern for display on the display, the pattern having a plurality of spot targets being arranged in two dimensions with each of the plurality of targets being separated from others of the plurality of targets in two dimensions;
• an imaging device positioned to detect at least a portion of the plurality of targets after interaction with the surface and to generate an electronic image thereof;
• a position controller configured to position the display and/or the imaging device at a plurality of positions along the optical axis to permit the imaging device to detect at least a portion of the plurality of targets after interaction with a portion of the surface at each of the plurality of positions along the axis;
• and
• an image analyzer configured to analyze the electronic image to determine if the plurality of targets in the electronic image are in expected locations following interaction with the surface.

A non-contact metrology system to measure a surface having an optical axis, comprising:

• a display positioned proximate a first side of the surface to be measured;
• a pattern generator configured to generate a pattern for display on the display, the pattern having a plurality of spot targets being arranged in two dimensions with each of the plurality of targets being separated from others of the plurality of targets in two dimensions;
• an imaging device positioned to detect at least a portion of the plurality of targets after interaction with the surface and to generate an electronic image thereof;
• a position controller configured to rotate the display and/or the imaging device to a plurality of positions about the axis to permit the imaging device to detect at least a portion of the plurality of targets after interaction with a portion of the surface at each of the plurality of rotational positions;
• and
• an image analyzer configured to analyze the electronic image to determine if the plurality of targets in the electronic image are in expected locations following interaction with the surface.

A non-contact metrology system to measure a surface having an optical axis, comprising:

• a display positioned proximate a first side of the surface to be measured;
• a pattern generator configured to generate a pattern for display on the display, the pattern having a plurality of spot targets being arranged in two dimensions with each of the plurality of targets being separated from others of the plurality of targets in two dimensions;
• an imaging device positioned to detect at least a portion of the plurality of targets after interaction with the surface and to generate an electronic image thereof;
• a position controller configured to rotate the surface to a plurality of positions about the axis to permit the imaging device to detect at least a portion of the plurality of targets after interaction with a portion of the surface at each of the plurality of rotational positions;
• and
• an image analyzer configured to analyze the electronic image to determine if the plurality of targets in the electronic image are in expected locations following interaction with the surface.