Abstract:
A mounting system deforms and compresses around a night vision tube within a housing, providing resistance to movement and dampening environmental shock. Also shown is a mounting system for a night vision tube in a night vision system that allows for retrofitting a smaller night vision tube.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application No. 62/021,952, filed on Jul. 8, 2014, and U.S. Provisional Application No. 62/097,503, filed on Dec. 29, 2014, both of which are incorporated herein by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Night vision systems generally comprise a number of components. A front lens system collects infrared light from the environment and provides the light to a night vision tube. The tube magnifies the number of received photons. In a typical tube, incoming light strikes a photocathode plate causing the emission of electrons through a microchannel plate. The electrons then form an image on a photocathode. An eye piece then conditions the image for the viewer. The tube is usually contained within a housing that is threaded at either end to mate with the front lens system and the eye piece. 
         [0003]    In general, night vision systems should be both small and mechanically robust. Often night visions system are handheld, mounted on device (such as a weapon), or mounted on a helm. For each of these scenarios, size and weight should be minimized. At the same time, night vision systems are typically used in the field and are exposed to extreme environments. 
       SUMMARY OF THE INVENTION 
       [0004]    Current mounting systems for night vision tubes result in night visions systems that are larger than required due to the need to shock dampen the night vision systems by using mass, excess size, and/or additional materials. This is largely due to the fragility and shape of the night vision tube. These conventional mounting systems contain a large proportion of metal parts and are otherwise bulky and utilize an ineffective mechanical design to ease the  felt recoil while also maintaining tube position within an augmentation/clone (clip-on) night vision system, for example. 
         [0005]    The present system can be used in various night vision designs and incorporates improved housing mounting designs. This system can also be made compatible with current front/rear optics, power supplies, modules, and components. 
         [0006]    A mounting system for a night vision tube in a night vision system is also described that allows for retrofitting a smaller night vision tube into a housing designed for a larger tube. 
         [0007]    In general according to one aspect, the invention features a night vision system comprising a housing, a night vision tube that magnifies incoming light, and a resilient sleeve between the housing and the night vision tube. 
         [0008]    In embodiments, the resilient sleeve is fabricated from plastic, such as PET plastic. 
         [0009]    A front compression buffer can also be used between a front of the sleeve and the night vision tube and the housing, and this compression buffer can be integral with the sleeve. 
         [0010]    In one embodiment, the sleeve has a port providing access to electrical contacts of the tube. In others, it has a shorten length. 
         [0011]    A retaining ring can be used to compress the sleeve against the housing. Here, the retaining ring engages threads in a rear of the housing. Further, a rear buffer can also be used, behind the night vision tube and the sleeve. 
         [0012]    In embodiments, a light pipe transmits light from a battery pack to a user&#39;s orbital field of view. 
         [0013]    The sleeve can include an electronics path for connecting power from a battery pack to electrical contacts on the night vision tube. This electronic path can include electrical conductors extending between the battery pack, through routing cutouts formed in the sleeve to the electrical contacts. 
         [0014]    In general according to another aspect, the invention features a night vision system comprising a housing designed to receive a larger diameter night vision tube. A smaller diameter night vision tube that magnifies incoming light is then installed within the housing. A  sleeve is used between the housing and the smaller diameter night vision tube to compensate for its smaller diameter. 
         [0015]    In general according to still another aspect, the invention features a method of mounting a smaller diameter night vision tube in a night vision system housing designed for a larger diameter night vision tube. This method comprises installing the smaller diameter night vision tube in the housing and compensating for its smaller diameter with a sleeve between the housing and the smaller diameter night vision tube. 
         [0016]    The above and other features of the invention including various novel details of construction and combinations of parts, and other advantages, will now be more particularly described with reference to the accompanying drawings and pointed out any claims. It will be understood that the particular method and device embodying the invention are shown by way of illustration and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    In the accompanying drawings, reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale; emphasis has instead been placed upon illustrating the principles of the invention. Of the drawings: 
           [0018]      FIG. 1  illustrates a scale exploded view of a night vision system according to the present invention; 
           [0019]      FIG. 2  is a reverse angle scale exploded view of the night vision system; 
           [0020]      FIG. 3  is a scale cross-sectional view of the night vision system; 
           [0021]      FIG. 4  is a cross-sectional perspective view and  FIG. 5  is a bottom perspective view showing a second embodiment of the night vision system including a compression sleeve that enables a 16 millimeter (mm) night vision tube to be retrofitted into a housing designed for an 18 mm tube and allows existing lenses to be retained (if desired); 
           [0022]      FIG. 6  is a perspective view showing a side-by-side comparison of a standard 18 mm tube and a 16 mm tube including the compression sleeve;  
           [0023]      FIG. 7  is a perspective exploded showing a variant design for the light pipe ring that interlocks with the rear buffer; 
           [0024]      FIG. 8  illustrates a scale exploded view of a night vision system according to a third embodiment; and 
           [0025]      FIG. 9  is a cross-sectional perspective view showing a fourth embodiment of the night vision system. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]      FIGS. 1-3  show a night vision system  100  constructed according to the principles of the present invention. 
         [0027]    A generally cubic-shaped hyper body functions as an outer housing  102  for the night vision system  100 . It has a wall section  280  to which a battery pack mounts. Along its central axis, the housing  102  has an entrance aperture  110  through which light enters the system  100 . Typically this light is collected by collection optics such as a front lens system, which is attached to the entrance aperture  110  via front threads  111  formed in the housing  102 . 
         [0028]    Light is transmitted to the user&#39;s eye through an exit aperture  112 , to which eyepiece optics are typically attached. The eyepiece or rear lens system mates to the housing  102  via rear threads  113  formed in the housing  102 . 
         [0029]    Inserted through the exit aperture are a series of components that are used to mount the night vision tube  138  in the housing  102 . 
         [0030]    An annular shaped front compression buffer  130  seats against a concave thrust surface  114  of the housing  102 . The front compression buffer  130  includes a keying feature  132 , which is a recess in the outer wall of the front buffer  130 , that interfaces with an indexing pin  134 , which pin is inserted through a side wall of the housing  102 . The indexing pin  134  and buffer keying feature  132  together assure that the compression buffer  130  has the proper rotational alignment with respect to the housing  102 . This front buffer  130  is deformable and is preferably constructed from polyethylene terephthalate (PET) plastic. 
         [0031]    Next, the largely cylindrical night vision tube  138  is inserted through the exit aperture  112  and seats against the front compression buffer  130 . The night vision tube  138   similarly includes a tube keying feature  136 , such as a recess in the outer wall of the tube  138  that interfaces with the indexing pin  134  and/or a male feature of the front compression buffer  130 , to ensure that the tube has a proper rotation alignment relative to the housing  102 . Two electrical contacts or power tabs  140  are located on the outer wall of the tube  138 . 
         [0032]    A hollow cylindrical compression sleeve  142  is then inserted over the night vision tube and seats against the thrust surface  116  of the front compression buffer. An electrical contact port  144  is formed through an outer wall of the skirt of the compression sleeve  142  to enable electrical access to the electrical contacts  140  of the tube  138 . 
         [0033]    A retaining ring  146  has a threaded outer peripheral surface  120  that mates with the internal rear threads  113  formed in the housing  102  in the exit aperture  112 . The retaining ring  146  is used to compress the compression sleeve  142  over the night vision tube  138  and against the compression buffer  130 . 
         [0034]    The combination of the compression buffer  130  and the compression sleeve  142  functions to sheath, isolate, and compress the night vision tube  138  in a moldable/deformable sheath. 
         [0035]    In some embodiments, this sleeve system  142  varies in skirt length and/or an additional rear deformable buffer(s) is/are included. Such a rear buffer is preferably annularly shaped like the front compression buffer  130 . Such rear buffer is preferably installed between the rear thrust surface  118  of the compression sleeve  142  or rear shoulder over the tube  138  and the retaining ring  142 . 
         [0036]    The compression sleeve  142  is a single or multiple piece design. An important feature, however is that the night vision tube  138  is sheathed from the front, sides and rear by the compression sleeve  142  that is under compression by retaining ring  146  engaging and thrusting against the rear thrust surface  118  and thus thrusting the forward end  148  of the sleeve  142  against the compression buffer  130 . 
         [0037]    In various designs, intermediate sleeve(s) may be included to support the night vision tube  138  between the front and rear compression elements, see front compression buffer  130  and rear thrust surface  118 , and to allow the inclusion of 16 mm night vision tube. The  16 mm tube requires an electric trace from the mid-rear of the standard 18 mm tube area to the front-mid area of the 16 mm tube surface area. 
         [0038]    The compression sleeve  142  is preferably fabricated from PET plastic. This plastic is resilient, exhibits only slight deformity while dampening shock, is not prone to cracking and is not fragile. It provides the right amount of deformation under compression to allow some molding fit while not over deforming and collapsing under recoil. 
         [0039]    The sizing of the resilient compression sleeve  142  is important, specifically between the maximum outside diameter (OD) of the night vision tube  138  and the internal diameter (ID) of the compression sleeve  142 . This should be a snug fit as the very slight irregularities of the tube circumference allow hand pressure to insert the tube  138  into the sleeve  142 . 
         [0040]    In some embodiments, a very slight angled ring projection  124  (see  FIG. 3 ) is provided that extends around the circumference of the internal corner of the plastic compression sleeve  142 . This functions as a forcing cone to the OD of the tube  138 . This then adds a bit more compression when the retaining ring  146  (preferably brass) is tightened down. 
         [0041]    The housing is metal, in this case aluminum. In other embodiments, the housing  102  is manufactured from titanium and other noble materials i.e., a material that resists chemical action, does not corrode, and is not easily attacked by acids. The inside of the housing  102  where the sleeve stops ( 114 ) is concave radius of about 0.09″, so it is semi-circular in cross-section. The compression sleeve  142  also has a radius with the same curvature, but male or convex profile. 
         [0042]    Under compression, the exoskeleton of the tube  138  crushes the PET compression sleeve  142  forward until it stops at the radius of the housing  102 . A few things occur here. The PET front compression buffer  130  deforms very slightly into the front of the housing  102 . The PET form fits to the micro abrasions of the tooling marks in the housing, it bulges slightly outward against the inside of the metal housing creating a compression/friction fit (anti-rotation), it deforms slightly inward (by design) to match the diameter of the light path and optics raceway.  
         [0043]    The brass retaining ring  124  and compression sleeve rear portion has a rear centering feature. As the rear retaining ring  124  is tightened, the compressing motion also centers the rear of the tube with a beveled edge that also deforms slightly. The front and rear PET components deform at the same time as the rear brass retaining ring  124  is tighten. This self-aligns and centers the tube  138  in the housing  102 . 
         [0044]    Total compression is roughly 0.005″ from the rear end of the brass retaining ring to the front of the PET front compression buffer  130 . 
         [0045]    In some examples, O-ring seals  150  are included in the front end, in a recess  152  formed in the leading edge of the compression buffer  130 . This allows the front lens system, which is attached to the entrance aperture  110  via front threads  111 , to be removed without losing the barometric integrity of the tube and electronics inside. Typically, the system is purged through a screw hole post assembly. Further, users can then add larger optics on this modularly without a complete disassembly. 
         [0046]      FIGS. 4 and 5  show a second embodiment of the night vision system  100  including a compression sleeve  142  that enables a 16 millimeter (mm) night vision tube to be retrofitted into a housing  102  designed for an 18 mm tube and allowing existing lenses to be retained (if desired). 
         [0047]    An advantage of this retrofit is that the 16 mm tube, while a non-standard tube, has a decreased mass relative to the 18 mm tube. Yet, new jumps in resolution allow the 16 mm tube to achieve similar resolution and meet other performance criteria. This retrofit is relevant both to legacy devices currently-fielded, and newer chassis in which the 18 mm is typical. 
         [0048]    In more detail, referring to  FIG. 4 , the compression sleeve  142  has thicker (A) outer skirt wall  250  in the radial direction than the embodiment of  FIG. 1 . This added thickness takes-up the extra room created by using the smaller 16 mm tube. Further, the front compression buffer  130  has a higher profile B in the longitudinal direction and is integrated with the compression sleeve  142  in this example to form a unitary piece. 
         [0049]    Added is an annular or washer-shaped rear buffer  154  between the compression sleeve  142  and the rear shoulder  252  of the night vision tube and the retaining ring  146 . The function of the rear buffer  154  is also to take up the extra space created when installing the  smaller 16 mm tube. In the illustrated embodiment, the front face  254  of the rear buffer  154  engages both the rear shoulder  252  of the tube  138  and the rear surface  256  of the compression sleeve  142 . The deformability of the compression sleeve  142  and rear buffer  154  ensures a tight/firm fit for the tube  138 . 
         [0050]    In the illustrated embodiment, a light pipe ring  258  is also provided. In the illustrated embodiment, transparent plastic is used that is in the shape of a ring around the tube. When the low battery LED blinks or the IR LED is “ON” those LED emissions travel from the battery pack, which mounts to the wall section  280  of the housing  102 , into the light pipe entrance aperture tabs  190  through the light pipe ring  258  and to the tabs  260  that extend into the field of view (FOV) as it is displayed orbital around the eyepiece. 
         [0051]    Currently, the contact points on the 18 mm tube are highly standardized among manufacturers. Due to its decreased size, the 16 mm contact points are not indexed to fit the standard battery housing contact points on the 18 mm tube. To enable to standard contact points to power the 16 mm tube, a set of leads travels from the typical contact point-through the sleeve-and to the 16 mm contact points. 
         [0052]      FIG. 5  shows the leads in the 16 mm/18 mm sleeve  142  that enable access to the 16 mm contact points on the tube  138 . 
         [0053]    Included in the compression sleeve  142  is an electronics path in which battery connector/power tabs  270 ,  272  are provided and located to receive power from the battery housing intended for the 18 mm tube. The battery housing is removed in the figure but normally seals against the square rim wall  280 . 
         [0054]    Two electrical leads or power traces  278 ,  279  run from the respective battery connector/power tabs  270 ,  272  to provide conductivity with and contact to the 16 mm tube contact point tabs  274 ,  276 . These tube contact tabs  274 ,  276  electrically contact the two electrical contacts or power tabs  140  on the outside of the 16 mm tube so it may be energized. 
         [0055]    In the illustrated embodiment, the tube contact point tabs  274 ,  276  are located in an oblong cutout  281  in the outer wall  250  of the compression sleeve. The battery connector/power tabs  270 ,  272  are located in a second cutout  282 . Finally routing cutouts  290 ,  292  house the electrical leads  278 ,  279 .  
         [0056]    The use of this sleeve  138  and rear buffer as a non-permanent and removable feature enables a user or manufacturer to switch back and forth between 16/18 mm tubes as required. The standard battery compartment/pack would not need to change nor would the main housing/chassis. Also, the front optics need not change either. Only the rear lens may need to be upgraded to travel a bit closer to the tube for focus. 
         [0057]    Due to the new 16 mm tube availability and performance updates, along with the significant weight savings this is a valuable option as a device manufacturer-particularly for helmet/head borne weight-providing possibly 70 gram reduction in a dual tube system. 
         [0058]      FIG. 6  is a side-by-side comparison of a standard 18 mm tube  138  and a 16 mm tube including the 16 mm/18 mm compression sleeve. 
         [0059]      FIG. 7  shows a variant design for a light pipe ring  258  that interlocks with the rear buffer  254 . 
         [0060]    This embodiment of the sleeve  138  also includes an annular thinned section  180 . The resulting region of reduced thickness of the sleeve  138  increases the resulting deformation of the length of the sleeve  138  for the same level of longitudinal stress. 
         [0061]      FIG. 8  shows a night vision system  100  according to third embodiment. 
         [0062]    Similar to the embodiment of  FIG. 1-3 , a generally cubic-shaped outer housing  102  for the night vision system  100  has a wall section  280  to which a battery pack mounts. 
         [0063]    In this embodiment, the front compression buffer  130  is integral with the hollow cylindrical compression sleeve  142 . Further, the longitudinal length of the skirt of sleeve  130  is shortened to expose the electrical contacts  140  of the tube  138 , avoiding the need for an electrical contact port. 
         [0064]    Here, a rear buffer  154  is used, with the light pipe ring  258  being sandwiched between the rear of the night vision tube  138  and the rear buffer  154 . The retaining ring  146  mates with the internal rear threads  113  formed in the housing  102  in the exit aperture  112 . The retaining ring  146  compresses the rear buffer  154  against the night vision tube  138  and the tube against the front compression buffer  130 .  
         [0065]    The illustrated compression sleeve  142  includes the annular thinned section  180  to control longitudinal compression. It further includes axially-directed thinned sections  182  to control the circumferential interference fit around the tube  138  and within the housing  102 . 
         [0066]      FIG. 9  shows a fourth embodiment of the night vision system  100  including a compression sleeve  142  and rear buffer  154  that enable a 16 millimeter (mm) night vision tube to be retrofitted into a housing  102  designed for an 18 mm tube. 
         [0067]    In this example, the rear buffer  154  has a scalloped inner edge profile  186 . This profile ensures an even distribution of stress over the rear shoulder  252  of the tube  138 . 
         [0068]    For stress distribution and to control the compressibility of the rear buffer  154 , axially-directed holes  188  are included through the length of the rear buffer  154 , arranged around the center port of the buffer  154 . 
         [0069]    While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.