Enhancements to integrated optical assembly

Abstract

An integrated optical assembly is provided, with enhancements that are particularly useful when the integrated optical assembly forms part of a laser radar system. The integrated optical assembly produces a reference beam that is related to the optical characteristics of a scanning reflector, or to changes in position or orientation of the scanning reflector relative to a source. Thus, if the scanning reflector orientation were to shift from its intended orientation (due e.g. to thermal expansion) or if characteristics of the scanning reflector (e.g. the index of refraction of the scanning reflector) were to change on account of temperature changes, the reference beam can be used to provide data that can be used to account for such changes. In addition, if the scanning reflector were to be positioned in an orientation other than the orientation desired, the reference beam can be used in identifying and correcting that positioning.

1 . An optical assembly for focusing a beam from a light source along a line of sight, where a lens, a scanning reflector and a fixed reflector are oriented relative to each other such that a beam from the light source is reflected by the scanning reflector to the fixed reflector, and reflected light from the fixed reflector is reflected again by the scanning reflector and directed along the line of sight through the lens, wherein the scanning reflector is moveable relative to the source, the lens and the fixed reflector, to adjust the focus of the beam along the line of sight, and wherein the optical assembly is configured to produce a reference signal that is related to the location of the scanning reflector relative to the source. 
     
     
         2 . The optical assembly of  claim 1 , wherein the optical assembly includes a lens between the source and the scanning reflector that is configured to produce a continuous collimated reference signal that traverses the scanning reflector at least twice and is then refocused on the source. 
     
     
         3 . The optical assembly of  claim 2 , wherein the lens is oriented off center, in relation to the source, to collimate the beam at a slight angle to the source, and the optical assembly is further configured so that after two passes through the scanning reflector, the reference signal is refocused on a reflector next to the source, traverses the scanning reflector at least twice more and is then refocused on the source. 
     
     
         4 . The optical assembly of  claim 1 , wherein the measurement and reference beams are directed through a pair of fibers, wherein the measurement beam produced through one fiber
 a. is reflected by a fold mirror,   b. traverses the scanning reflector,   c. is reflected by the fixed reflector,   d. traverses the scanning reflector again, and is directed along the line of sight through the lens, and   wherein the reference beam produced through the other fiber   a. traverses the scanning reflector,   b. is reflected by an optical element that shifts the reference beam,   c. traverses the scanning reflector again, and   d. is transmitted back to the reference beam fiber.   
     
     
         5 . A method for producing useful data in an optical assembly for focusing a beam from a light source along a line of sight, where the optical assembly includes a lens, a scanning reflector and a fixed reflector are oriented relative to each other such that a beam from the light source is reflected by the scanning reflector to the fixed reflector, and reflected light from the fixed reflector is reflected again by the scanning reflector and directed along the line of sight through the lens, and wherein the scanning reflector is moveable relative to the source, the lens and the fixed reflector, to adjust the focus of the beam along the line of sight, the method comprising producing produce a reference signal that is related to the orientation of the scanning reflector relative to the source. 
     
     
         6 . The method of  claim 5 , wherein the reference signal is produced between the scanning reflector and the source by a continuous collimated reference beam that traverses the scanning reflector at least twice and is then refocused on the source. 
     
     
         7 . The method of  claim 6 , wherein the collimated reference beam is collimated at a slight angle to the source, and configuring the optical assembly is further configured so that after two passes through the scanning reflector, the reference signal is refocused on a reflector next to the source, traverses the scanning reflector twice more and is then refocused on the source. 
     
     
         8 . The method of  claim 5 , wherein as the optical assembly is focusing the beam along the line of sight the reference signal provides data to account for changes in the refraction or reflection characteristics of the optical assembly. 
     
     
         9 . The method of  claim 5 , wherein the reference signal is used in producing data to account for changes in the reflection or refraction characteristics of the scanning reflector due to changes in the intended orientation of the scanning reflector. 
     
     
         10 . The method of  claim 5  wherein the reference signal is used in producing data to account data to account for changes in the reflection or refraction characteristics of the scanning reflector due to changes in the angular orientation of the scanning reflector. 
     
     
         11 . The method of  claim 5 , wherein the reference signal is used in producing data to account for changes in the reflection or refraction characteristics of the scanning reflector due to changes in the temperature of the scanning reflector. 
     
     
         12 . A method for manufacturing a structure, comprising:
 producing the structure based on design information;   obtaining shape information of structure by using of the method of  claim 4 ;   comparing the obtained shape information with the design information.   
     
     
         13 . The method for manufacturing the structure according to  claim 11  further comprising reprocessing the structure based on the comparison result. 
     
     
         14 . The method for manufacturing the structure according to  claim 12 , wherein reprocessing the structure includes producing the structure over again.