CROSS REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to night vision goggles, and more particularly to simulated night vision goggles, which simulate actual use of night vision goggles in the field during daylight conditions. 
     2. Description of the Prior Art 
     Night vision goggles have proven to be essential to pilots, police, and the military, during nighttime maneuvers. Night vision goggles display monochrome light with limited resolution and limited contrast, producing a limited depth of field and a narrow field of view. Night vision goggles are also heavy, and affect the user&#39;s balance, mobility, and movement. The combined optical and physical effects of night vision goggles often degrade a beginning user&#39;s performance. Therefore, training in the use of night vision goggles is important and at times critical, prior to engaging in difficult and dangerous activity at night. Night vision goggle users may be more easily and safely trained in daylight conditions, where the instructor can more easily observe the physical conditions of the environment, adding a margin of safety for the users of the night vision goggles during training, and allowing performance assessment of user activities. 
     U.S. Pat. No. 5,420,414 issuing to E. Wentworth on May 30, 1995, discloses a night vision goggle simulator utilizing a replaceable fiber optic lens assembly. This applicant patent uses a replaceable insert where the image intensification tube (light amplifying system) is located. However, instead of a fiber optic bundle used by Wentworth, applicant uses a simple direct view optical system comprised of lenses, a narrow band-width green filter, a mesh screen, a star filter and an optional prism (to invert images), as components of the viewing insert or apparatus. 
     U.S. Pat. No. 6,196,845 issuing to H. Streid on Mar. 6, 2001 discloses a visual display system for simulating night vision goggles across a large dynamic range. 
     U.S. Pat. No. 5,581,271 issuing to W. Kraemer on Dec. 3, 1996 discloses a head mounted visual display for simulation and training, utilizing a real time video image. 
     U.S. Pat. No. 5,413,483 issuing to F. Witt Ill, on May 9, 1995, discloses a night vision goggle simulator for night vision training. An instructor pilot uses a microprocessor based controller for controlling each of the six liquid crystals. 
     U.S. Pat. No. 4,948,957 issuing to G. Rusche on Aug. 14, 1990 discloses a method for training infrared imager users by making a video recording of an infrared scene, producing an infrared image from the recording and projecting the image onto a screen, and of converting the projected image into a visible image at a users infrared imager. 
     U.S. Pat. No. 4,202,601 issuing to J. Burbo et al. on May 13, 1980, discloses a training aid for use with a night vision apparatus, utilizing a variable density Polaroid filter array and blue-green filter mounted on a pair of goggles. The polarizing plates are varied to simulate nighttime conditions. 
     PCT patent application publication no. WO 01/33531 filed 29 Oct. 1999 discloses a simulated image low light viewing system utilizing a graphical or video image display which is projected in a region of the user&#39;s field of view. 
     The following U.S. Patents are representative of night vision goggles: U.S. Pat. Nos. 6,195,206; 6,088,165; 5,912,721; 5,852,291; 5,347,119; 5,331,459; 4,463,252; and DES351,397. 
     The following U.S. Patents are representative of mounting assemblies for mounting night vision equipment; U.S. Pat. Nos. 5,856,811; 5,726,671; 5,467,479; 5,448,318; 5,506,730; 5,408,086; 5,339,464; 5,307,204; 5,226,181; 5,225,932; 5,179,735; 4,907,296; 4,703,879; 4,697,783; 4,689,834; 4,670,912; 4,592,096; 4,449,787; and DES358,830. 
     BRIEF SUMMARY OF THE INVENTION 
     The night vision goggle training apparatus disclosed herein, simulates the size, feel, and handling of actual night vision goggles. A green filter lens is part of the optical components and is used to simulate nighttime goggle viewing conditions. The image intensification system used in night vision goggles is eliminated, limiting use of the training goggles to daytime conditions. A high intensity flashlight may be added to simulate an IR light source. A 3X magnification attachment, similar to the magnification attachment used on night vision goggles, and a compass attachment, may be used on the training goggles. The out of balance weight of the night vision goggles apparatus is identical to actual night vision goggles. Brightness control is simulated by an attenuation filter. The blooming effect of lights in night vision goggles may be simulated/indicated with a star filter. A thin mesh screen is used to reduce image acuity and to simulate scintillation or ghosting effects during low light or rapid motion, which occur during use of actual night vision goggles. The objective focus and diopter adjustment are identical to night vision goggles. The fatigue and stress is reduced, and daylight training with these training goggles allows gradual adjustment. The cost per unit is about ten to twenty percent of the cost of actual night vision goggles, enabling a large force to be economically trained in the use of night vision goggles prior to deployment of the more expensive actual night vision goggles. The durability and life cycle of the night vision training devices is very high (about 10 to 20 years), and use of the training devices will greatly increase the life cycle of the actual night vision goggles. 
     The field of view, magnification, acuity, weight, monochrome image color, depth perception, helmet/thead mount assemblies, faceplate and eyecups of the simulated night vision goggles are similar or identical to actual night vision goggles. 
    
    
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
     These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings, wherein: 
     FIG. 1 is a perspective view of simulated night vision goggles. 
     FIG. 2 is a front view of the simulated night vision goggles shown in FIG.  1 . 
     FIG. 3A is a side view of the simulated night vision goggles shown in FIG.  1 . 
     FIG. 3B is a side view of a snap-on filter accessory, showing upper and lower extensions used to engage the first and second grooves in the custom housing. 
     FIG. 4 is a back view of the simulated night vision goggles shown in FIG.  1 . 
     FIG. 5 is a top view of the simulated night vision goggles shown in FIG.  1 . 
     FIG. 6 is a perspective view of a standard PVS-7 night vision goggle, with optic filter insert shown adjacent to the night vision goggle. 
     FIG. 7 is a perspective view of a standard PVS-14 night vision goggle, with an optic filter insert shown adjacent to the night vision goggle. 
     FIG. 8 is a perspective view of a standard ANVIS night vision goggle, with optic filter inserts shown adjacent to the night vision goggle. 
     FIG. 9 is a an injection mold housing similar to the standard PVS-7 night vision goggle shown in FIG. 6, with an optic filter insert mounted in the lens housing. 
     FIG. 10 is an injection mold housing similar to the standard PVS-14 night vision goggle shown in FIG. 7, with an optic filter insert mounted in the lens housing. 
     FIG. 11 is an injection mold housing similar to a standard ANVIS night vision goggle shown in FIG. 8, with optic filter inserts mounted in each lens housing. 
     FIG. 12 is a top view of a wide field of view night vision goggle training apparatus. 
     FIG. 13 is a front view of the wide field of view night vision goggle training apparatus shown in FIG.  12 . 
    
    
     These drawings are provided for illustrative purposes only and should not be used to unduly limit the scope of the present invention. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The simulated night vision goggle apparatus  100 , disclosed herein, may be used in a custom housing  110 , similar to the housing shown in FIG.  1  through FIG.  5 . 
     Altemately, the simulated night vision goggle apparatus  100 , disclosed herein, may be used to simulate night vision in the same way as actual night vision goggle housings  112 ,  114 ,  116  as shown in FIG.  6  through FIG. 8, with the expensive lens systems removed, and an optic filter insert  120  installed within the housing  110 , in the same optical location as the image intensifier tube in an actual night vision goggle. 
     The simulated night vision goggles  100  image filtering combination may also be adapted for use with molded housings  113 ,  115 ,  117 , as shown in FIG.  9  through FIG. 11, used on actual night vision goggles, and shown with the simulator insert  120 . 
     A high intensity flashlight may be added to simulate an IR light source. A 3X magnification attachment, and a compass attachment, may also be used on the training goggles. 
     As shown in FIG.  1  through FIG. 5, the simulated night vision goggles  100  comprise a housing  110  having a left side  22 , a top side  24 , a right side  26 , a bottom side  28 , a front side  30  and a back side  32 . The back side  32  includes a large aperture  33  forming an interior chamber  20  bounded by the left side  22 , to top side  24 , the right side  25 , the bottom side  28  and the front side  30 . The back side  32  has a face guard  35 , which is preferably curved  34  to fit the contour of a user&#39;s face, as best shown in FIG.  5 . 
     A latch assembly  36  is provided to releasably secure the housing  110  to a user&#39;s headgear or helmet (not shown). The latch assembly  36  is preferably a spring loaded latch assembly  36  compatible with standard night vision goggle head mount and helmet assemblies, typically located on the top side  24  of the housing  110 . Snaps, hook and loop fasteners, screws, and sleeves, or other known releasable fastening means  40  may also be provided to releasably secure the housing  110  to the user&#39;s headgear and/or to a suitable face cushion  42 , and to attach the green filter  50 , star filter  51 , and a mesh screen  48  to the housing  110 . Preferably, the face cushion  42  is made of real or simulated leather or lamb skin, and curves  34  to conform to a users face, as best shown in FIG.  5 . 
     The front side  30  of the housing  110  is sized to receive an optic filter attachment  44 , such as a Plexiglas cover  46 , a mesh screen  48 , a green filter  50  and a star filter  51 . First and second grooves  52 ,  53  are provided for ease of attachment of additional optic filters  54 , such as a neutral density filter  56 , or a green filter  50 . Preferably, the filter attachments are snap-on filters  58 , as best shown in FIG.  3 B. Snap-on filters  58  include upper and lower extensions  57 ,  59  which engage the first groove  52  located on the top side  24  of the custom housing  110 , and a second groove  53  located on the bottom side  28  of the custom housing  110 . 
     Weights  90  are preferably added to the night vision goggle training apparatus  100 , as shown in FIG. 1, to simulate the actual weight of various night vision goggles. Weight  91  simulates the actual weight of ANVIS night vision goggles. Weight  92  simulates the actual weight of PVS-7 night vision goggles. Weight  93  simulates the actual weight of PVS-14 night vision goggles. These weights  91 ,  92 ,  93  are selected to train the user in actual night vision goggle use, and each weight  90  may be used on the night vision goggle training apparatus  100  disclosed herein. 
     As shown in FIG. 2, FIG.  3  and FIG. 4, a light guard  60  is made of opaque flexible material, and positioned to extend below the bottom side  28  of the housing  110 , in a manner to prevent light leaks in proximity to the user&#39;s neck, jaw or lower face region. The light guard is hinged to raise up so look-under capability is possible for users. 
     A partition  62  extends within the housing  110  between a first viewing aperture  64  and a second viewing aperture  66 , as best shown in FIG.  4 . The first viewing aperture  64  and the second viewing aperture  66  extend through the front side  30  of the housing  110 , as shown in FIG.  3 A and FIG.  4 . The partition  62  prevents both eyes from seeing through the opposite aperture, and is formed as shown in dashed line in FIG.  3  and FIG.  5 . The partition  62  may be molded as part of the housing  110 , or a pliable part may be added at assembly. The partition  62  is shaped to avoid contact with the users nose, when the housing  110  is positioned upon the users face. The pliable part of the partition will prevent injury if contact with the user&#39;s nose occurs. 
     A first groove  52  and second groove  53  are preferably provided on the top side  24  and bottom side  28  of the custom housing  110 , in proximity to the front side  30  of the custom housing  110 , as shown in FIG.  3 A. The first and second grooves  52 ,  53  are provided for ease of adding snap-on accessories  58 , such as a fine mesh screen  48 , used to simulate a step-down in grain (reduced acuity) in the viewed image, when seen through the first and second viewing apertures  64 ,  66 . 
     Snap-on accessories  58  preferably have an upper extension  57  positioned to engage the first groove  52  located on the top side  24  of the custom housing  110 , and a lower extension  59  positioned to engage the second groove  53  located on the bottom side  28  of the custom housing  110 , as best shown in FIG.  3 B. In this embodiment, the snap-on accessories  58  are easily slidable on or off the custom housing  110 , without requiring tools. Snap-on accessories include green, narrow band-width filters to simulate brightness (gain) adjustments, and a metal cover  61  where no light enters through either aperture to simulate the monocular night viewing device (PVS-14). 
     As shown in FIG. 6, a PVS-7 housing  112  may be used, with the expensive image intensification tube removed, and an inexpensive optic filter insert  120  positioned within the housing  112 . The optic filter insert  70  preferably comprises: a fine mesh screen  72  similar to the fine mesh screen  48  used in housing  110 , one or more intermediate lenses  74 , a green narrow band-width filter  76  similar to the green filter used in housing  110 . A star pattern flat plate filter  78 , may also be incorporated into the optic lens insert  70 . 
     The PVS-7 housing  112  will provide a custom fit, weight, size and feel similar to an actual PVS-7 housing, with identical control positions, enabling the user to become familiar with the control positions on actual night vision goggles. 
     As shown in FIG. 7, a PVS-14 housing  114  may be used, with the expensive image intensification tube removed, and an inexpensive alternate optic filter insert  80  positioned within the housing  114 . The alternate optic filter insert  80  preferably comprises: a fine mesh screen  72  similar to the fine mesh screen  48  used in housing  110 , one or more intermediate lenses  74 , a green narrow band-width filter  76  similar to the green filter used in housing  110 . A star pattern flat plate filter  78 , and an image inverter  84  may also be incorporated into the alternate optic lens insert  80 . The image inverter  84  in the PVS-14 housing preferably incorporates a PORRO or ABBE prism  82 . The PVS-14 housing  114  will provide a custom fit, weight, size and feel similar to an actual PVS-14 housing  114 , with identical control positions to improve daylight training simulation. 
     As shown in FIG. 8, an ANVIS housing  116  may also be used, with the expensive image intensification tube removed, and an inexpensive alternate optic filter insert  80  positioned within the housing  114 . The alternate optic filter insert  80  preferably comprises: a fine mesh screen  72  similar to the fine mesh screen  48  used in housing  110 , one or more intermediate lenses  74 , a green narrow band-width filter  76  similar to the green filter used in housing  110 . A star pattern flat plate filter  78 , and an image inverter  84  may also be incorporated into the alternate optic filter insert  80 . The image inverter will incorporate a PORRO or ABBE prism  82 . The ANVIS housing  116  will provide a custom fit, weight, size and feel similar to an actual ANVIS housing  116 , with identical control positions to improve daylight training. 
     FIG. 9 is a perspective view of an injection molded PVS-7 housing  113 , which is molded to simulate the size, weight, control positions and feel of an actual PVS-7 night vision goggle housing  112 , with the expensive image intensification tube and electrical control unit removed, and an inexpensive optic filter insert  70  positioned within the housing  112 . The optic filter insert  70  preferably comprises: a fine mesh screen  72  similar to the fine mesh screen  48  used in housing  110 , one or more intermediate lenses  74 , a green narrow band width filter  76  similar to the green filter used in housing  110 . A star pattern flat plate filter  78  is also incorporated into the optic lens insert  70 . The PVS-7 injection molded housing  113  will provide a custom fit, weight, size and feel similar to an actual PVS-7 housing  112 , with identical control positions. 
     As shown in FIG. 10, an injection molded PVS-14 housing  115  may be used, with the expensive image intensification tube removed, and an inexpensive alternate optic filter insert  80  positioned within the housing  114 . The alternate optic filter insert  80  preferably comprises: a fine mesh screen  72  similar to the fine mesh screen  48  used in housing  110 , one or more intermediate lenses  74 , a green narrow band-width filter  76  similar to the green filter used in housing  110 . A star pattern flat plate filter  78 , may also be incorporated into the optic lens insert  70 . 
     Additionally, the injection molded PVS-14 113 housing will incorporate an alternate optic lens insert  80  incorporating a PORRO or ABBE prism  82  to invert the image. The injection molded PVS-14 housing  113  will provide a custom fit, weight, size and feel similar to an actual PVS-14 housing  114 , with identical control positions to improve daylight training. 
     As shown in FIG. 11, an injection molded ANVIS housing  117  may be used, with the expensive image intensification tubes removed, and inexpensive alternate optic filter insert  80  positioned within the injection molded housing  117 . The alternate optic filter inserts  80  preferably each comprise: a fine mesh screen  72  similar to the fine mesh screen  48  used in housing  110 , one or more intermediate lenses  74 , a green narrow band-width filter  76  similar to the green filter used in housing  110 . A star pattern flat plate filter  78 , and an image inverter  84  will also be incorporated into the alternate optic filter insert  80 . 
     Additionally, the injection molded ANVIS housing  117  will preferably incorporate an image inverting insert  80  incorporating a PORRO or ABBE prism  82 . The injection molded ANVIS housing  117  will provide a custom fit, weight, size and feel similar to an actual ANVIS housing  116 , with identical control positions to improve daylight training. 
     FIG. 12 is a top view of a custom, wide field of view night vision goggle training apparatus  94 . The field of view shown in FIG. 2 is modified to include an angled left side  95 , a front side  96 , and an angled right side  97 . This effectively increases the field of view to 100 degrees or more. 
     FIG. 13 is a front view of the custom, wide field of view  94  night vision goggle training apparatus  102 , shown in FIG.  12 . The filters  44 ,  46  (shown in FIGS. 2,  3  and  4 ) are adapted to conform to the wide angled field of view  94 . Note that four apertures  64 ,  65 ,  66  and  67  are used to create the wide angled field of view  94 . Two additional pliable partitions  62  are used to separate the four apertures  64 ,  65 ,  66 ,  67 . The partitions  62  prevent both eyes from seeing through the adjacent aperture. As previously noted, the pliable partition  62  may be molded as part of the housing  102 , or a pliable part may be added at assembly. The partitions are preferably shaped to avoid contact with the user, when the housing  102  is positioned upon the user&#39;s face. 
     In use, the simulated night vision goggle apparatus  100  is worn in daylight conditions to train future users to wear and operate actual night vision goggles. The instructor will be able to observe the trainees and the surrounding terrain under daylight conditions, to improve safety and performance. The simulated night vision goggles will train users with inexpensive equipment that effectively simulates actual night vision goggle use. This provides a low cost training alternative, enabling the user of night vision goggles to develop the skills required to master the use of actual night vision goggles, before embarking on dangerous and unknown situations. 
     The user will place the face guard  35  located on the back side  32  of the simulated night vision goggles  100  against their face, positioning their nose and eyes within the interior chamber  20  in the housing  102 . The partition  62  is positioned within the custom housing  102  against the front side  30  of the housing  102 , to avoid direct contact with the user&#39;s nose during use. First and second apertures  64 ,  66  are positioned on each side of the partition  62 , enabling the user to view two distinct views through the simulated night vision goggles  100 . This improves depth perception, while simulating actual conditions of night goggle use. 
     The simulated night vision goggles  100  disclosed herein have a curved face guard  35 ,  34 , which preferably includes a face cushion  42  for comfort, and to reduce stray light penetration  42 ,  60  during use. The simulated night vision goggles  100  includes a latch assembly  36  compatible with a user&#39;s helmet or headgear to simulate actual use. The latch assembly  36  is preferably a spring loaded latch mechanism sized to engage and selectively release the simulated night vision helmet or headgear. Additional snaps, hook and loop fasteners, or other known releasable fastening means  40  are preferably provided to secure the simulated night vision goggle housing  110  to the face cushion  42 , and to the helmet or headgear  38 . 
     Multiple filter attachments  44  are releasably secured to the front side  30  of the simulated night vision goggles  100 . One such filter attachment  44  is a Plexiglas cover  46 . Another attachment is a fine mesh screen known to simulate the grain structure of actual night vision goggles  112 ,  114  or  116 . Another attachment is a green narrow band-width filter. Additional filters  54  may be added, such as neutral density filter  56  and/or a star pattern flat plate filter  78 , to simulate various night vision conditions. Preferably, a prism image inverter  84  is also provided as part of the optic filter insert  80 . 
     First and second grooves  52 ,  53  are provided for ease of attaching additional filters  54 . Preferably, the first groove  52  extends across the top side of the custom housing  110 , and the second groove  53  extends across the bottom side of the simulated night vision goggle housing  110 . The additional filters  54  preferably have upper and lower extensions  57 ,  59 , which are positioned to engage the first and second grooves  52 ,  53  to releasably secured the additional filters  54  to the custom housing  110 . 
     A flexible hinged light guard  60  is attached to the custom housing  110  beneath the bottom side  28 , to prevent light leaks in proximity to the user&#39;s neck. 
     As previously noted, the simulated night vision goggle assembly  100  may utlize a custom housing  110 , actual PVS-7, PVS-14 or ANVIS housings  112 ,  114 ,  116 , or injection molded PVS-7, PVS-14 or ANVIS housings  113 ,  115 ,  117 , without departing from the scope of this disclosure, or the following claims. 
     The cost per unit is about ten to twenty percent of the cost of actual night vision goggles, enabling a large force to be trained in the use of night vision goggles prior to deployment of the more expensive actual night vision goggles. The durability and life cycle of the night vision training goggles is greatly increased over actual night vision goggles. 
     Weights  90  are preferably added to the night vision goggle training apparatus  100 , as shown in FIG. 1, to simulate the actual weight of various night vision goggles. Weight  91  simulates the actual weight of ANVIS night vision goggles. Weight  92  simulates the actual weight of PVS-7 night vision goggles. Weight  93  simulates the actual weight of PVS-14 night vision goggles. These weights  91 ,  92 ,  93  are selected to train the user in actual night vision goggle use, and each weight  90  may be selectively used on the night vision goggle training apparatus  100  disclosed herein. In the wide field of view apparatus shown in FIG. 12 and 13, only a single weight would be used to equal the weight of the system. 
     The custom night vision goggle training apparatus  94  shown in FIG.  12  and FIG. 13, provides a wide field of view, not provided by custom housing  110 . The field of view is modified in FIG. 12 to include an angled left side  95 , a front side  96 , and an angled right side  97 . This effectively increases the field of view to 100 degrees or more. 
     FIG. 13 is a front view of the custom, wide field of view night vision goggle training apparatus  94 , shown in FIG.  12 . The filters  44 ,  46  are adapted to conform to the wide angled field of view  94 . Note that four apertures  64 ,  65 ,  66  and  67  are used to create the wide angled field of view  94 . Two additional pliable partitions  62  are used to separate the four apertures  64 ,  65 ,  66 ,  67 . The partitions  62  prevent both eyes from seeing through the adjacent aperture. 
     Although the invention has been described herein by way of exemplary embodiments, variations in the structure and methods described herein may be made without departing from the spirit and scope of the invention. For example, the invention has been disclosed with a custom housing  110 . Also shown are actual night vision goggle housings, which may alternately be used. A third embodiment is provided with molded housings which closely replicate actual night vision goggle housings. One of average skill in this art may readily adapt the custom housing  110 , without departing from the spirit or scope of this disclosure, or the following claims.
The night vision goggle training apparatus simulates the size, feel and handling of actual night vision goggles. A narrow band-width green filter is positioned over the viewing port, to simulate nighttime viewing conditions. The image intensification system used in night vision goggles is eliminated; limiting use of the training goggles to daytime use. The out of balance weight of the night vision goggles is identical to actual night vision goggles. Brightness control is simulated by attenuation filters that fit over the objective lens. The blooming effect of lights is simulated with a star filter. A thin, fine mesh screen is used to simulate reduced acuity, scintillation and ghosting effects during low light or rapid motion, which occur during use of actual night vision goggles. The objective focus and diopter adjustment are identical to night vision goggles. The cost per unit is about ten to twenty percent of the cost of actual night vision goggles, enabling a large force to be trained in the use of night vision goggles prior to deployment of the more expensive actual night vision goggles. The durability and life cycle of the night vision training goggles is greatly increased over actual night vision goggles. The field of view, magnification, acuity, weight, monochrome image color, depth perception, helmet/head mount assemblies, faceplate and eyecups of the simulated night vision goggles is similar or identical to actual night vision goggles.