Imaging Assembly

Abstract

A imaging assembly for generating a light beam suitable for sintering comprises a lamp housing and a lamp mounted in the lamp housing comprising a filament and a lamp base, wherein the lamp is oriented with the lamp base to the side of the filament. The imaging assembly further comprises a reflector, an aperture, and at least one condenser lens configured to focus light emitted by the filament through the aperture. The imaging assembly further comprises a set of achromatic doublet lenses, each achromatic doublet lens comprising three surfaces optimized to focus light at three wavelengths, wherein the set of achromatic doublet lenses focuses light over a range including the three wavelengths. The imaging assembly further comprises an outer lens, wherein the focused light beam exits the imaging assembly through the outer lens.

1 . An aperture system for a solid imaging system comprising:
 a surface comprising a layer of sinterable powder;   a light source;   at least one aperture comprising a first aperture, said first aperture interposed between the light source and the layer of sinterable powder; and   an optical system comprising one or more lenses, wherein said optical system is configured to focus light from said aperture onto said layer of sinterable powder;   wherein said optical system comprises an object plane, and said first aperture coincides with said object plane such that an image of said first aperture is projected onto said layer of sinterable powder, said image being characterized by an outer diameter, and   wherein said light focused on the layer of sinterable powder is characterized by a point spread function, and a value of the point spread function in proximity to the outer diameter of said image is less than a value of the point spread function in proximity to the center of the image.   
     
     
         2 . The aperture system of  claim 1 , further comprising an aperture disc, wherein said aperture disc comprises said at least one aperture and at least one opaque area. 
     
     
         3 . The aperture system of  claim 2 , further comprising a stepper motor configured to rotate said aperture disc to interpose a selected aperture between said light source said layer of sinterable powder to define a shape of a light spot projected on said layer of sinterable powder. 
     
     
         4 . The aperture system of  claim 1 , wherein said at least one aperture comprises a plurality of selectable apertures of different sizes. 
     
     
         5 . The aperture system of  claim 1 , wherein a shape of said first aperture comprises one or more polygons. 
     
     
         6 . The aperture system of  claim 5 , wherein said shape of said first aperture is a polygon selected from a group consisting of a circle, a rectangle, a slit and a square. 
     
     
         7 . The aperture system of  claim 5 , wherein said shape of said first aperture comprises multiple parallel slits configured to sinter a cross-hatch pattern in said layer of sinterable powder. 
     
     
         8 . The aperture system of  claim 7 , wherein said multiple parallel slits are curvilinear. 
     
     
         9 . An imaging system for a solid imaging system, wherein said imaging system comprises:
 a first optical subsystem comprising a light source and at least one lens;   a second optical subsystem comprising at least one achromatic doublet lens; and   an aperture positioned in an object plane of said second optical system;   
       wherein said first optical subsystem is configured to focus light from said light source on an entrance pupil of said at least one achromatic doublet lens, and wherein an image of said aperture at the object plane is projected on a layer of sinterable powder. 
     
     
         10 . The imaging system of  claim 9 , wherein said first optical system and said second optical system are aligned with a main optical axis; and wherein said light source comprises a filament centered over and aligned perpendicularly to said main optical axis. 
     
     
         11 . The imaging system of  claim 9 , wherein said light source is a tungsten halogen lamp. 
     
     
         12 . The imaging system of  claim 9 , further comprising a reflector comprising a mirror, the mirror configured to reflect said light from the light source back onto said light source in a direction of said second optical subsystem. 
     
     
         13 . The imaging system of  claim 12 , wherein said mirror is coated with a material selected from the group consisting of: dielectric, broadband dielectric, and gold. 
     
     
         14 . The imaging system of  claim 9 , wherein said second optical system further comprises an outer lens positioned on an exterior of said imaging system and in proximity to said layer of sinterable powder. 
     
     
         15 . The imaging system of  claim 14 , further comprising a heating means to heat said outer lens to or above a predetermined threshold temperature. 
     
     
         16 . The imaging system of  claim 15 , wherein said predetermined threshold temperature is about an ambient temperature of said layer of sinterable powder. 
     
     
         17 . The imaging system of  claim 15 , wherein said predetermined threshold temperature is about a melting temperature of said layer of sinterable powder. 
     
     
         18 . The imaging system of  claim 15 , wherein said heating means exposes said outer lens to said light source before a sintering operation. 
     
     
         19 . The imaging system of  claim 15 , wherein the heating means is configured to conduct heat from the light source to the outer lens. 
     
     
         20 . The imaging system of  claim 19 , wherein the heating means is configured to conduct air heated by the light source to the outer lens. 
     
     
         21 . The imaging system of  claim 20 , wherein the heating means comprises a fan for directing the heated air to the outer lens via a channel. 
     
     
         22 . The imaging system of  claim 21 , wherein the air is further heated by the doublet lens, thereby cooling the doublet lens. 
     
     
         23 . An imaging system for a solid imaging system, comprising:
 a light source;   an outer lens positioned on an exterior of said imaging system and in proximity to a layer of sinterable powder; and   a temperature control system configured to heat an outer lens to at least a predetermined temperature;   wherein an image is projected on a surface comprising said layer of sinterable powder.   
     
     
         24 . The imaging system of  claim 23 , wherein said temperature control system is further configured to dissipate heat from said light source. 
     
     
         25 . The imaging system of  claim 23 , wherein the imaging system further comprises at least one achromatic doublet lens, and wherein said temperature control system is further configured to dissipate heat from said at least one achromatic doublet lens. 
     
     
         26 . The imaging system of  claim 23 , further comprising a source cell associated with said light source and a doublet cell associated with said least one achromatic doublet lens, wherein said temperature control system maintains said source cell below a first predetermined operational temperature and said temperature control system maintains said doublet cell below a second predetermined operational temperature. 
     
     
         27 . The imaging system of  claim 26 , wherein said first predetermined temperature is higher than second predetermined temperature. 
     
     
         28 . The imaging system of  claim 27 , wherein a cooling element of said temperature control system is used to cool said doublet cell before cooling said source cell. 
     
     
         29 . The imaging system of  claim 28 , wherein said cooling element is forced air. 
     
     
         30 . The imaging system of  claim 26 , further comprising a thermal barrier separating said doublet cell and source cell. 
     
     
         31 . The imaging system of  claim 26 , wherein said first predetermined operational temperature is about 350° C. 
     
     
         32 . The imaging system of  claim 26 , wherein said second predetermined operational temperature is about 85° C. 
     
     
         33 . The imaging system of  claim 26 , wherein at least one of said light source and said at least one achromatic doublet lens is mounted in a material with high thermal conductivity and wherein a cooling element of said temperature control system is directed over said material. 
     
     
         34 . The imaging system of  claim 26 , wherein said temperature control system heats said outer lens using waste heat of said temperature control system, wherein said waste heat is generated by said light source. 
     
     
         35 . The imaging system of  claim 34 , wherein said waste heat comprises heat in a stream of forced air, wherein said heat is collected from at least one of said light source and said at least one achromatic doublet lens. 
     
     
         36 . The imaging system of  claim 23 , wherein said predetermined temperature is about an ambient temperature of said layer of sinterable powder. 
     
     
         37 . The imaging system of  claim 23 , wherein said predetermined temperature is about a melting temperature of a material comprising said layer of sinterable powder.