Abstract:
A handheld thermal imager includes a housing defining a cavity. A lens barrel has a first end portion  and a second end portion. The lens barrel is at least partially disposed within the cavity. A lens is coupled to the lens barrel first end portion. A resilient buffer member supports the lens barrel within the cavity. A thermal sensor is coupled to the lens barrel second end portion. A processing module receives signals from the thermal sensor. A display is coupled to the processing module for displaying a temperature characteristic of a scene.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 61/452,778, filed Mar. 15, 2011, the contents of which are herein incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    The present invention relates to portable electronic imaging devices, such as a thermal imager. 
         [0003]    A thermal imager is a thermal detection device which detects and displays a temperature characteristic of a scene. Thermal imagers are used by professionals in a variety of industries to assess temperatures of objects within a field-of-view (“FOV”) of the thermal imager. Such devices may be used in a variety of environments, and may be subject to rough handling or even being dropped upon a hard surface. 
       SUMMARY 
       [0004]    In one embodiment, the invention provides a handheld thermal imager. The thermal imager includes a housing defining a cavity. A lens barrel has a first end portion and a second end portion. The lens barrel is at least partially disposed within the cavity. A lens is coupled to the lens barrel first end portion. A resilient buffer member supports the lens barrel within the cavity. A thermal sensor is coupled to the lens barrel second end portion. A processing module receives signals from the thermal sensor. A display is coupled to the processing module for displaying a temperature characteristic of a scene. 
         [0005]    In another embodiment the invention provides an imaging device. The imaging device includes a housing assembly having a first housing member and a second housing member. The first housing member and the second housing member define a cavity. A lens barrel has a first end and a second end. The lens barrel is at least partially disposed in the cavity. A resilient buffer includes a ring-shaped body and at least one radial extension member. The ring-shaped body is annularly disposed about the lens barrel between the first end and the second end. The radial extension member is coupled to the housing assembly to support the lens barrel within the cavity. A lens is coupled to the lens barrel first end. A thermal sensor is resiliently coupled to the lens barrel second end and substantially supported by the first housing member and not the second housing member. 
         [0006]    Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view of a thermal imager according to one aspect of the invention. 
           [0008]      FIG. 2  is an alternative perspective view of the thermal imager of  FIG. 1 . 
           [0009]      FIG. 3  is a perspective view of a detector assembly of the thermal imager of  FIG. 1 . 
           [0010]      FIG. 4  is a cross sectional view of a portion of the thermal imager of  FIG. 1 , with impact dampening features shown in exploded view. 
           [0011]      FIG. 5  is a cutaway perspective view of a portion of the thermal imager of  FIG. 1 , with an additional impact dampening feature shown in exploded view. 
           [0012]      FIG. 6  is a cutaway perspective view of a portion of the thermal imager of  FIG. 1 . 
           [0013]      FIG. 7  is an alternative cutaway perspective view of a portion of the thermal imager of  FIG. 1 . 
           [0014]      FIG. 8  is a perspective view of a battery pack of the thermal imager of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. 
         [0016]      FIGS. 1 and 2  illustrate a thermal imager  10 . The thermal imager  10  includes a housing  12 . The housing  12  includes a right housing half  14  and a left housing half  16 , with a cavity  18  ( FIGS. 5 and 6 ) defined by the housing halves  14  and  16 . 
         [0017]    Referring to  FIGS. 1 and 2 , the housing  12  includes a handle portion  20 , a trigger portion  22 , a lens portion  24 , a user input portion  26 , and a display portion  28 . The handle portion  20  defines a battery pack receptacle  30  for receiving a battery pack  32 . The display portion  28  includes a visual display  34  and the user input portion includes one or more user input devices  36  (e.g., buttons), respectively. 
         [0018]    Bumpers  38  are coupled to the housing  12 . The bumpers  38  are formed of a resilient material, such as co-molded or overmolded rubber or synthetic rubber. The purpose of the bumpers  38  is to increase the impact time should the thermal imager  10  be dropped or bumped into a hard surface. In the illustrated embodiment, the bumpers  38  surround the lens portion  24 , the display portion  28 , and edges  40  of the housing  12 . Additional resilient material forms gripping surfaces  42  on the handle portion  18 . The bumpers  38  may be coupled to the housing  12  by a co-molding process, or they may be separately formed and attached to the housing  12  by mechanical, thermal, or adhesive means. 
         [0019]      FIG. 3  illustrates a detector assembly  44  of the thermal imager  10 . The detector assembly  44  includes, among other things, a lens barrel  46 , a thermal sensor  48 , and a visual camera  50  disposed beneath the lens barrel  46 . The visual camera  50  is covered by a clear plastic shield  52  for protection (see  FIG. 1 ). In some embodiments, an LED work light may be incorporated into the thermal detector assembly, adjacent the visual camera. 
         [0020]    Referring to  FIG. 3 , the lens barrel  46  includes a cylindrical body  54  with a first end  56  and a second end  58 . An annular groove  60  is defined in the cylindrical body  54  of the lens barrel  46 , between the first and second ends  56  and  58 . Referring now to  FIG. 5 , a resilient buffer ring  64  is disposed within the annular groove  60  of the lens barrel  46 . The resilient buffer ring  64  includes an upper radial extension member  66  and a lower radial extension member  68 . The extension members  66  and  68  are the only portion of the resilient buffer ring  64  that is coupled to the surrounding housing  12 . The resilient extension members  66  and  68  thereby support the lens barrel  46  within the housing  12 , while substantially reducing impact forces transferred from the housing  12  to the lens barrel  46 . 
         [0021]    As shown in the exploded view of  FIG. 5 , the resilient buffer ring  64  includes a plurality of circumferentially arranged teeth  70 . When installed within the annular groove  60 , the teeth  70  fit inside corresponding recesses  72  formed in the annular groove  60 . The tooth and recess arrangement  70  and  72  is provided to minimize rotation of the lens barrel  46  relative to the housing  12 . 
         [0022]    With reference to  FIG. 4 , a cross-sectional view of the thermal imager  10 , the optics for the detector assembly  44  include a fixed inner lens  74  and an adjustable aspheric lens  76 . The lenses  74  and  76  are made of, for example, glass, quartz glass, fluorite, plastic, acrylic, Germanium, or the like. The inner lens  74  is housed within the lens barrel  46 . The aspheric lens  76  is manually adjustable for focus via a focus ring  78  accessible from the exterior of the thermal imager  10  (see  FIGS. 1 and 2 ). The focus ring  78  is rotatably coupled to the lens barrel  46 . The focus ring  78  may be formed of a resilient material, such as rubber or synthetic rubber, to substantially reduce the transfer of impact forces to the lens barrel  46 . Referring to  FIG. 2 , a lens cover  80  is selectively coupled to the focus ring  78 . The lens cover  80  includes a resilient portion or is formed entirely of a resilient material in order to substantially reduce the transfer of impact forces to the detector assembly  44 . 
         [0023]    Referring to  FIG. 3 , the thermal sensor  48  of the detector assembly  44  is, for example, a 160 pixel by 120 pixel (i.e., 160×120) un-cooled microbolometer. The microbolometer generates signals corresponding to a thermal image that is 160 pixels wide and 120 pixels long. Each pixel of the microbolometer provides temperature measurements having an accuracy within approximately 2%. The thermal sensor  48  is highly sensitive to heat and temperature changes. In order to properly compensate for this sensitivity, additional sensors may be used to measure temperature fluctuations caused by both internal and external heat sources. 
         [0024]    A flexible circuit cable  82  electrically connects the thermal sensor  48  and visual camera  50  to a processing module that includes a printed circuit board assembly (PCBA)  84 . The flexible circuit cable  82  provides the detector assembly  44  with improved impact resistance by minimizing the transfer of mechanical shock to connector contacts and soldered joints within the detector assembly  44 . 
         [0025]    As also shown in  FIG. 4 , a plurality of rubber grommets  84  are installed between the lens barrel  46  and the thermal sensor  48 . One configuration of these grommets  84  is shown in exploded view. As best illustrated in  FIG. 7 , four grommets  84  are arranged symmetrically about an end plate  86  that is coupled to the lens barrel  46 , though in other embodiments, more or fewer grommets may be used. The grommets  84  are configured to substantially reduce the transfer of impact forces from the lens barrel  46  to the thermal sensor  48 . 
         [0026]    With reference to  FIGS. 6 and 7 , the detector assembly  44  is coupled to a substantially rigid mounting plate  88 . The mounting plate  88 , in turn, is coupled to the housing  12 . More specifically, the mounting plate  88  is coupled to the right housing half  14  of the housing  12 , via a plurality of threaded fasteners  90  that engage apertures  92  formed in the right half  14  of the housing  12 . The threaded fasteners  90  may be, for example, cap or button head screws. Resilient washers may be disposed between the threaded fasteners and the mounting plate to provide a degree of impact resistance. 
         [0027]    With reference to  FIG. 4 , the visual display  34  includes an external display lens  94  covering an underlying electronic display  96 . The electronic display  96  may be, for example a liquid crystal display (“LCD”), a light-emitting diode (“LED”) display, an organic LED (“OLED”) display, an electroluminescent display (“ELD”), a surface-conduction electron-emitter display (“SED”), a field emission display (“FED”), or the like. In some embodiments, the electronic display  96  is a 3.5″ thin-film transistor (“TFT”) LCD. In other embodiments, the electronic display  96  is a super active-matrix OLED (“AMOLED”) display. 
         [0028]    A resilient gasket  98  is disposed between the external display lens  94  and the electronic display  96 . The resilient gasket  98  substantially reduces the transfer of impact forces from the external display lens  46  to the underlying LCD panel  48 . As shown in exploded view, the resilient gasket  98  has a rectangular profile  100 , matching the profile of the electronic display  96  and display lens  94 . The resilient gasket  98  may be formed from a microcellular polyurethane, such as PORON®, or another resilient material. A flexible frame member  102  supports the electronic display  96  internally. 
         [0029]    With reference to  FIG. 8 , the battery pack  32  includes a casing  104 , an outer housing  106  coupled to the casing  104 , and a plurality of battery cells (not visible) positioned within the casing  104 . The casing  104  is shaped and sized to engage the receptacle  30  in the thermal imager  10 . The casing  104  includes an end cap  108  to substantially enclose the battery cells within the casing  104 . The illustrated end cap  108  includes two power terminals  110  configured to mate with corresponding power terminals of the thermal imager  10 . In other embodiments, the end cap  108  may include terminals that extend from the battery pack  32  and are configured to be received in receptacles supported by the thermal imager  10 . The terminals couple to a battery circuit (not shown). 
         [0030]    The casing  104  and power terminals  110  substantially enclose and cover the terminals of the thermal imager  10  when the battery pack  32  is positioned in the receptacle  30  ( FIGS. 1 and 2 ). That is, the battery pack  32  functions as a cover for the receptacle  30  and terminals of the thermal imager  10 . Once the battery pack  32  is disconnected from the thermal imager  10  and the casing  104  is removed from the receptacle  30 , the battery terminals on the thermal imager  10  are generally exposed to the surrounding environment. 
         [0031]    Referring to  FIG. 8 , the outer housing  106  is coupled to the casing  104  substantially opposite the end cap  108  and surrounds a portion of the casing  104 . In the illustrated construction, when the casing  104  is inserted into or positioned within the corresponding receptacle  30  in the thermal imager  10 , the outer housing  106  generally aligns with outer surfaces of the handle portion  18  ( FIGS. 1-2 ). In this construction, the outer housing  106  is designed to substantially follow the contours and general shape of the handle portion  18 . In such embodiments, the outer housing  106  effectively increases (e.g., extends) the length of the handle portion  18  of the thermal detection device  10 . 
         [0032]    Referring to  FIG. 8 , two actuators  112  (only one of which is shown) and two tabs  114  are formed in the outer housing  106  of the battery pack  32 . The actuators  112  and the tabs  114  define a coupling mechanism  116  for releasably securing the battery pack  32  to the thermal imager  10 . Each tab  114  engages a corresponding recess formed in the receptacle  30  of the thermal imager  10  to secure the battery pack  32  in place. The tabs  114  are normally biased away from the casing  104  (i.e., away from each other) due to the resiliency of the material forming the outer housing  106 . Actuating (e.g., depressing) the actuators  112  moves the tabs  114  toward the casing  104  (i.e., toward each other) and out of engagement with the recesses such that the battery pack  32  may be pulled out of the receptacle  30  and away from the thermal imager  10 . 
         [0033]    The battery pack  32  is also configured to connect and provide power to additional devices such as drills, saws, grease guns, right angle drills, pipe cutters, lasers, impact wrenches, impact drivers, reciprocating saws, inspection cameras, radios, worklights, screwdrivers, wall scanners, infrared thermometers, clamp meters, digital multimeters, fork meters, multi-tools, grinders, band saws, jig saws, circular saws, rotary hammers, generators, vacuums, and the like. 
         [0034]    Thus, the invention provides, among other things, a thermal imager with improved impact resistance characteristics. Various features and advantages of the invention are set forth in the following claims.