Surface topography measurement systems

Abstract

A topographical measurement system uses an imaging cartridge formed of a rigid optical element and a clear, elastomeric sensing surface configured to capture high-resolution topographical data from a measurement surface. The imaging cartridge may be configured as a removable cartridge for the system so that the imaging cartridge, including the rigid optical element and elastomeric sensing surface can be removed and replaced as a single, integral component that is robust/stable over multiple uses, and easily user-replaceable as frequently as necessary or desired. The cartridge may also usefully incorporate a number of light shaping and other features to support optimal illumination and image capture.

1 - 39 . (canceled) 
     
     
         40 . A device comprising:
 an optical element having an interior including a rigid, optically transparent material;   a first surface of the optical element, the first surface including a region with an optically transparent surface for capturing images through the optical element;   a second surface of the optical element opposing the first surface;   a center axis of the optical element passing through the first surface and the second surface;   a layer of optically transparent elastomer disposed on the second surface and attached to the second surface, a first side of the layer adjacent to the second surface of the optical element having a second index of refraction matched to a first index of refraction of the second surface, and a second side of the layer opposing the second surface of the optical element having an optical coating with a predetermined reflectance;   a sidewall around the interior of the optical element between the first surface to the second surface, the sidewall including one or more light shaping features configured to control an illumination of the second surface through the sidewall; and   a mechanical key on an exterior of the optical element for enforcing a predetermined position of the optical element within a fixture of an imaging system, the mechanical key including at least one radially asymmetric feature about the center axis for enforcing a unique rotational orientation of the optical element within the fixture of the imaging system.   
     
     
         41 . The device of  claim 40  wherein the sidewall includes a continuous surface forming a frustoconical shape with the first surface and the second surface. 
     
     
         42 . The device of  claim 40  wherein the sidewall includes a continuous surface forming a truncated hemisphere with the first surface and the second surface. 
     
     
         43 . The device of  claim 40  wherein the sidewall includes two or more discrete planar surfaces. 
     
     
         44 . The device of  claim 40  wherein the one or more light shaping features include a diffusing surface to diffuse point sources of incoming light along the sidewall. 
     
     
         45 . The device of  claim 40  wherein the one or more light shaping features include a polished surface to refract incoming light. 
     
     
         46 . The device of  claim 40  wherein the one or more light shaping features include a curved surface to focus incident light. 
     
     
         47 . The device of  claim 40  wherein the one or more light shaping features include a neutral density filter with graduated attenuation to compensate for a distance from the sidewall on the second surface. 
     
     
         48 . The device of  claim 40  wherein the one or more light shaping features include one or more color filters. 
     
     
         49 . The device of  claim 40  wherein the one or more light shaping features include a non-normal angle of the sidewall to the second surface. 
     
     
         50 . The device of  claim 40  wherein the one or more light shaping features include a geometric feature. 
     
     
         51 . The device of  claim 40  wherein the one or more light shaping features include an optical film. 
     
     
         52 . The device of  claim 40  wherein the one or more light shaping features include a micro-lens array. 
     
     
         53 . The device of  claim 40  wherein the one or more light shaping features include a plurality of micro-replicated optical features. 
     
     
         54 . The device of  claim 40  wherein the first surface includes a curved surface providing lens to optically magnify an image from the second surface for the imaging system. 
     
     
         55 . The device of  claim 40  wherein the first surface includes an aspheric surface shaped to address optical aberrations in an image captured through the optical element from the second surface. 
     
     
         56 . The device of  claim 40  wherein the first surface includes a freeform surface shaped to mitigate geometric distortion in an image captured through the optical element from the second surface. 
     
     
         57 . The device of  claim 40  wherein the mechanical key includes one or more magnets. 
     
     
         58 . The device of  claim 40  wherein the mechanical key includes a plurality of protrusions including at least one protrusion having a different shape than other ones of the plurality of protrusions for enforcing the unique rotational orientation of the optical element within the fixture of the imaging system. 
     
     
         59 . The device of  claim 40  wherein the mechanical key includes three protrusions shaped and sized to form a kinematic coupling with the fixture of the imaging system.