Abstract:
An adjustable illumination apparatus includes an illumination source having a housing carrying an illuminatable element. A mount is adapted to surround an imaging system lens. An extensible and retractable support has first and second ends mounts the illumination source to the mount. First and second connections movably couple the first and second ends of the support to the mount and the illumination source. The support includes one or more telescoping legs or a cross link bar assembly. In one aspect, the apparatus includes multiple illumination sources. The connections allow each illumination source to be independently positioned relative to other illumination sources. The illuminatable elements in each illumination source may be independently controlled.

Description:
CROSS-REFERENCE TO CO-PENDING APPLICATION 
     This application claims priority benefit of the filing date of U.S. Provisional Patent Application Ser. No. 60/951,756, filed Jul. 25, 2007, for an “Adjustable Light,” the contents of which are incorporated herein in its entirety. 
    
    
     BACKGROUND 
     The present invention relates, in general, to vision optical systems and, more particularly, to illumination devices for imaging optics. 
     Machine vision optical systems are employed to obtain a digital image of an object in the field of view of the optical system for analysis. In order to accurately image the object, so as to be able to determine if the object has any surface defects, or to determine the dimensions of the object, illumination is typically required. 
     Previously, illumination devices in the form of a ring of illuminatable segments, such as light bulbs, LEDs, have been mounted in a ring shaped holder encircling the lens of the camera. This illumination device projects light onto an object spaced from the lens so as to provide sufficient illumination for the lens to obtain an accurate image of the object. Controls to vary the intensity or number of LEDs that are illuminated are known. 
     However, since machine vision optics are used with objects having a wide range of size, shapes and surface topography, it is still desirable to have an adjustable illumination source which can be positioned to provide adequate illumination onto any point on an object as well as be able to provide illumination to a wide range of object sizes and surface topographies. 
     SUMMARY 
     An illumination apparatus for an imaging system having a lens mounted on a housing includes an illumination source with a housing and at least one illuminatable element carried within the housing for emitting light through an opening in the housing, a mount adapted to surround an imaging system lens, at least one extensible and retractable support having first and second ends, the support mounting the illumination source to the mount, a first connection movably coupling the first end of the support to the mount, and a second connection movably coupling the second end of the support to the illumination source. 
     In one aspect, the at least one support and the illumination source are pivotally movable through the first connection with respect to the mount. 
     In one aspect the at least one support and the illumination source are pivotally movable through the first connection with respect to the illumination source. 
     The first connection and the second connection may be a swivel connection swivally connecting the at least one support and one of the mount and the illumination source. 
     The illumination source may be a plurality of illumination sources, and the at least one support includes a plurality of supports. Each illumination source is movably coupled to one of the supports. 
     The support may be an extensible and retractable leg. The leg includes first and second telescopingly engaged leg portions. 
     In one aspect, the leg includes a pair of legs, each leg coupled to one of a pair of first connections and to one of a pair of second connections. 
     The support may be a cross bar linkage having a pair of first ends and opposed pair of second ends, a pair of first connections coupling the first ends to the mount, and a pair of second connections coupling the second ends to the illumination source. 
     At least one of the pair of first movable connections and at least one of the pair of second connections may be movable in a track carried in one of the mount and the illumination source. 
     The illuminatable element may include at least one light emitting diode. 
     In one aspect, the illumination source may include a plurality of illumination sources, The at least one illuminatable element in the illumination source may include a plurality of illumination elements. The illuminatable elements in each illumination source can be independently controllable with respect to the illuminatable elements in other illumination sources. 
     In another aspect, the at least one illuminatable element includes a plurality of illuminatable elements; and the intensity of the illuminatable elements, with illumination source being variable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The various features, advantages and other uses of the disclosed adjustable light will become more apparent by referring to the following detailed description and drawing in which: 
         FIG. 1  is a side elevational view of one aspect of an adjustable light usable in a machine vision optical system, with the legs of the adjustable light shown in a partial extended position; 
         FIG. 2  is a bottom elevational view of the adjustable light shown in  FIG. 1 ; 
         FIG. 3  is a perspective view showing one of the legs of the light in an extended position; 
         FIG. 4  is a side perspective view of the adjustable light with all the legs depicted in an extended position; and 
         FIGS. 5A and 5B  are side elevational views of another aspect of an adjustment means for the adjustable light, shown respectively in retracted and extended positions. 
     
    
    
     DETAILED DESCRIPTION 
     As shown in  FIGS. 1-4 , an illumination source  8  for a microscope, camera or other machine vision optical system  10  is illustrated. 
       FIGS. 1-4  depict by way of example only the bottom portion of a machine vision optical system  10 , such as a camera or microscope which has a lens  12  mounted on a bottom surface  14 . 
     The adjustable light source includes a mount on base  20  which may take any shape, such as a polygonal shape or the illustrated circular shape, and have a bottom wall  22  with a plurality of mounting tabs  24  extending radially outward from the bottom wall  22 . Each mounting tab  24  is attachable to the bottom surface  14  of a housing  11  of the optical system  10 , such as by means of fasteners which extend through apertures  26  in each of the mounting tabs  24  into the housing  11 . The bottom surface  22  of the mount or base  20  has a central aperture for disposing the mount  20  around the lens  12  on the bottom surface  14  of the optical system housing  11 . An outer sidewall  26  projects from the bottom wall  22 . 
     One or more telescoping legs, with four legs  30 ,  32 ,  34  and  36  being illustrated by way of example only in  FIGS. 1-4 , are carried on the mount on base or mount  20 . Each leg  30 ,  32 ,  34  and  36  is formed, of at least one or more legs, with two legs  38  and  40  being depicted by way of example only for each leg pair  30 ,  32 ,  34  and  36 . 
     Each leg  38  and  40  is formed of a plurality of telescoping segments  42 ,  44  and  46  by way of example only. Any number of segments and any length segments may be employed to form each of the legs  38  and  40 . For example, each leg  38  and  40  may be extended from a fully retracted total length of about three inches, to a total expanded length of about six to eight inches. 
     One end  50  of each leg  38  and  40  is pivotally connected to a swivel mount  52  which is fixed to the bottom surface  22  of the mount  20  and projects away from the bottom surface  22  in the direction of the side wall  26 . The swivel mount  52  and the pivotal connection between the swivel mount  52  and one end of each of the legs  38  and  40  may be constructed to provide up to 180° movement along one axis or a 360° universal movement along a plurality of axes. 
     The opposite end of each of the legs  38  and  40  is connected to a second swivel joint  54  which provides the same 180° or 360° movement as the swivel mount  52 . 
     An illumination source holder or housing  60  is pivotally connected to the swivel joints  54 . This enables the illumination source holder  60  to move with telescoping extension and retraction of the legs  38  and  40  as well as pivotal movement of the legs  38  and  40  about the first end connection to the swivel joints  52  on the mount  20 . Each light holder  60  may also be individually pivoted about the swivel joint  54  to direct the light emanating from the light source carried by the holder  60  in various directions. 
     An illumination source  70  is carried within each holder  60  and connected to electric power, typically by one or more wires or conductors, not shown, which extend through one or both of the legs  38  and  40  of each pair of legs  30 ,  32 ,  34  and  36  to a terminal connection within the housing  11  of the optical system  10 . The conductors may be coiled to provide extensibility and retractability as the legs  38  and  40  telescope in length. Alternately, the legs  38  and  40  themselves may be employed as the conductor to supply power to the illumination source  70 . 
     The holder  60  may take any shape, such as the generally cubical shape shown in  FIGS. 1-4  wherein holder  60  has a generally rectangular cross section. Each holder  60  may take other shapes, such as a circular shape, or other polygonal shapes. The holder  60  may be formed with a linear longitudinal extent or with a shallow radius or curve. All of the holders  60  need not have the same shape depending upon the application and the object to be illuminated. 
     The illumination source  70 , by way of example only, may be formed of a plurality of LEDs  72  arranged in a bank or array within the holder  60 . Any number of LEDs  72  may be used to form the illumination source  70 . The LEDs  72  may be arranged in a single elongated row, in multiple rows and columns, or in any configuration in the holder  60 . 
     Each illumination source  70  may be controlled by a control means, which includes one or more selector switches or buttons  82  carried on the housing  11  on the optical system  10 . Each illumination source  70  may be turned on or off independently of the illumination sources  70  in the other holders  60 . The intensity of each illumination source  70  may also be varied as an entire group, or in each individual holder, etc., by means of a suitable selector switch. 
     A control switch may also be provided to illuminate only certain of the LEDs  72  within each holder  60  independent of other LEDs  72  in the same holder  60 . 
     The LEDs  72  may be provided in any color useful for imaging applications. Thus, the LEDs  72  may emit light in colors of red, blue, yellow, white, black, etc. Controls  80 ,  FIG. 1 , may be provided for activating certain color LEDs  72  in one or more holders  60  as necessary for a particular imaging application. All of the switching functions can also be implemented by on display-mouse control through software. 
     A support  90  shown in  FIG. 4 , is provided, by way of example only, for each leg pair  30 ,  32 ,  34 , and  36 . The support  90  spans each leg  38  and  40  of each leg pair  30 ,  32 ,  34 , and  36 . By way of example only, the support  90  is formed of a light weight plastic and has spaced projections  92  at opposite ends to provide a snap on capability around each of the legs  38  and  40 . The support  90  maintains each leg  38  and  40  of each leg pair  30 ,  32 ,  34 , and  36  at a consistent spacing during telescoping extension and retraction movements of each leg  38  and  40 . 
     In use, with an object located in the field of view of the lens  12 , the holders  60  are positioned relative to the lens  12  by extending or retracting the telescoping legs  38  and  40  of each leg pair  30 ,  32 ,  34 , and  36  to the desired length relative to the lens  12  and/or the object to be imaged. Each holder  60  can be pivoted about the swivel joints  54  on the respective leg pair  30 ,  32 ,  34 , and  36  to direct the light from the illumination source  70  in each holder  60  in the proper direction to illuminate the desired surface feature of the object being imaged while minimizing stray light. 
     It will be understood that the amount of extension and retraction and thereby the length of each leg pair  30 ,  32 ,  34 , and  36  as well as the angular position of the holder  60  relative to its leg pair  30 ,  32 ,  34 , and  36  may be adjusted independently of the other leg pairs  30 ,  32 ,  34 , and  36  and holders  60  so as to direct the light from the illumination source  70  in each holder  60  in the desired direction toward the object being imaged. 
     It is also possible to replace the telescopic legs  38  and  40  of the leg pair  30 ,  32 ,  34  and  36  with a pantograph type criss-cross bar assembly  101  as shown in  FIGS. 5A and 5B . In this case, one joint  104  at the mount  20  and one joint  106  at the housing  60  connected to one of the links of the bar assembly  101  is slidable in tracks  103  and  105 , respectively. Another pair of joints  108  and  110  pivotally connected to other links of the bar assembly  101  are fixed to the mount  20  and the housing  60 , respectively. All other swivel action is the same as described above for the telescopic legs.