Abstract:
Swimming goggles that are shaped by approximately profiling the goggles to the swimmer&#39;s head resulting in the goggles having a minimal tendency to be pulled off or pulled ajar from the swimmer&#39;s head by hydrodynamic forces while exhibiting minimal hydrodynamic drag. Optical arrays molded into the lenses of the goggles permit standard vision both underwater and above the water.

Description:
This application is a continuation-in-part of U.S. patent application Ser. No. 12/807,721, having the filing date of Sep. 13, 2010, and which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/276,470, having the filing date of Sep. 12, 2009. 
    
    
     TECHNICAL FIELD 
     Swimming goggles that exhibit a hydrodynamically streamlined profile and provide for standard vision both underwater and above water. 
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to swimming goggles for covering and protecting the eyes of a swimmer while enhancing the swimmer&#39;s vision. In particular this invention relates to swimming goggles that geometrically approximate a hydrodynamically streamlined profile with respect to the swimmer&#39;s head while simultaneously permitting standard vision when the swimmer&#39;s eyes are either above or below the water surface. More particularly, the invention relates to lens structures for swimming and diving goggles. 
     Swimming goggles, especially those for competitive swimmers, should provide several functions and exhibit several characteristics. Firstly, the goggles should protect the swimmer&#39;s eyes from the irritations of the water. In swimming pools these irritations are caused from chemical disinfectants such as chlorine, bromine, or ozone. Additional irritations are caused from incompatible pH levels, ionic concentrations, and chemical buffers in the pool water. Secondly, goggles should provide for standard vision both underwater and above water. Thirdly, the goggles should perform these functions without requiring the swimmer to alter his or her diving entry into the pool for fear of the goggles being displaced from the swimmer&#39;s head by hydrodynamic forces and moments. Fourthly, the goggles preferably exhibit no more hydrodynamic drag than if the swimmer were swimming without goggles. Prior art goggles have failed to satisfy all of these functions and characteristics. 
     Swimming goggles have been made to match a section of a hydrodynamically streamlined contour to the face. (For example, see  FIG. 1 .) Shaping goggles this way permits a swimmer to dive into the pool, turn and push off from walls, and swim with minimal concern that the goggles might be pulled off or pulled ajar due to hydrodynamic forces and moments. Additionally, the hydrodynamic drag of such goggles is less than that for coplanar lens swimming goggles, an advantage for competitive swimmers. The deficiency of these types of prior art goggles is that underwater binocular-like viewing is not standard. Incoming parallel rays diverge as they refract through the hydrodynamically streamlined lenses. (For example, see  FIG. 2 .) This requires that the swimmers eyes point in convergent directions to attain binocular focus while viewing underwater; the swimmer must adjust his or her eyes into a cross-eyed orientation to attain binocular vision. It is difficult to rapidly toggle back and forth from a cross-eyed orientation for underwater binocular viewing to a straight-ahead orientation for above water binocular viewing. Double images are observed when viewing underwater with both eyes looking straight ahead. Using these prior art goggles may cause headache, vertigo, or induce nausea. 
     To attain standard vision when wearing swimming goggles requires that parallel rays remain parallel when passing through the goggle lenses both above and below the water. Specifically, if two rays are parallel as they enter the lenses of the goggles with one ray passing through the left lens and on a trajectory to then intersect the center of rotation of left eye and the other ray passing through the right lens and on a trajectory to then intersect the center of rotation of the right eye, then they shall also be approximately parallel after both rays pass through the lenses of the goggles. 
     Keeping rays parallel as they pass through the left and right lenses of goggles has been accomplished in the prior art in several ways. One technique disclosed by Bengtson et al., U.S. Pat. No. 4,051,557, utilizes coplanar sections of plastic or glass as part of the left and right lenses. Widenor, U.S. Pat. No. 3,027,562, discloses a flat section of plastic in front of the eyes which then curves in the peripheral region of viewing outside of binocular vision. Another technique, disclosed by Hagan, U.S. Pat. No. 3,672,750, uses a section of a sphere as the outer surface of each uniform thickness lens with the center of radius of each sphere close to the center of rotation of each eye. Here, any ray which is on a trajectory to intersect the center of rotation of an eye and is within the field of view of that eye is normal to the lens surface. Flory, U.S. Pat. No. 5,313,671, discloses use of a section of a cylinder instead of a sphere. These techniques preclude matching the contour of the face with a goggle that is minimally intrusive into the free stream of water such as shown in  FIG. 1 . 
     Swimming goggles of the prior art may also add optical corrections similar to those found in corrective prescription glasses to reduce the effects of visual deficiencies such as myopia, hypermetropia, and astigmatism. For coplanar lenses these corrections are often added to each of the inner lens surfaces with the outer surface of each lens remaining flat. Most commonly offered are simple spherical corrections in whole or half diopter steps. 
     Reducing the tendency of standard vision goggles from being pulled off or ajar has been addressed by the prior art in several ways. Drew, U.S. Pat. No. 4,279,039, discloses attaching coplanar lens goggles directly to the swim cap. Van Atta et al., U.S. Pat. No. 7,475,435, discloses reducing coplanar lens size. Fukasaw, U.S. Pat. No. 6,996,857, discloses adding fillets to the protruding sections of coplanar lens goggles. 
     Prior art refinements enhancing standard vision include blackening whole sections of the viewing field as disclosed by Yokota, U.S. Pat. No. 7,165,837. 
     SUMMARY OF THE INVENTION 
     The present invention relates to swimming goggles having lenses with outer surfaces which geometrically approximate a portion of a hydrodynamically streamlined profile while simultaneously providing for standard vision both above and below the water. 
     The present invention comprises swimming goggles with an optical array formed into both the inner and outer surfaces of the lenses of the goggles. The outer optical arrays have two functions. Firstly, the outer surfaces of the outer optical arrays geometrically approximate a portion of a hydrodynamically streamlined profile. Secondly, outer arrays optically approximate the outer surface of an optically appropriate lens section such as coplanar lenses. The inner array optically approximates the inner surface of an optically appropriate lens section without geometrically conflicting with human anatomy. 
     Goggles of this invention are less prone to being pulled off or pulled ajar from a swimmer&#39;s head by hydrodynamic forces or moments, particularly during a diving entry into the water. They also exhibit reduced hydrodynamic drag compared to other goggles that provide for standard vision. This is true both for the unsteady and for the steady hydrodynamic environments. 
     These and other benefits of this invention will become apparent from the following description by reference to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of prior art goggles. 
         FIG. 2  is a top sectioned view of the prior art goggles of  FIG. 1 . 
         FIG. 3  is another perspective view of prior art goggles; 
         FIG. 4  is a sectioned view of prior art goggles wherein part of each lens is a spherical or cylindrical section; 
         FIG. 5  is a perspective view of an embodiment of goggles of the present invention; 
         FIG. 6  is a top sectioned view of the goggles of  FIG. 5 ; 
         FIG. 7  is another sectioned view of the goggles of  FIG. 5 ; 
         FIG. 8  is a sectioned side view showing another embodiment of the hydrodynamically streamlined goggles of the present invention; 
         FIG. 9  is a sectioned view of another embodiment of the hydrodynamically streamlined goggles of the invention; 
         FIG. 10  is a perspective view of goggles of the invention having an alternative optical array pattern; 
         FIG. 11  is a sectioned view of an eye and a portion of a lens; 
         FIG. 12  is a sectioned view of the eyes and a portions of the lens; and 
         FIG. 13  is a sectioned side view showing several outer contour lines through this section of the goggle lens of the instant invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1-4  show prior art goggles which are discussed in the Background of the Invention. The present invention relates to lenses which are used in swimming and diving goggles which essentially hold the lenses in position with respect to the eyes and face of the wearer. It is within the purview of the present invention to be used in connection with any means which hold lenses in position. 
     In one embodiment illustrated by  FIG. 5 ,  FIG. 6 , and  FIG. 7 , swimming goggles  10  are shown having lens frames  11 ,  12 , lenses  13 ,  14 , nose-bridge  15 , head strap  16 , and eye seals  17 . The lenses are shown having an exterior surface and incorporating optical arrays as part of both the inner surfaces  20 ,  21  and the outer surfaces  18 ,  19  of the exterior surfaces of the lenses  13 ,  14 , respectively. Each optical array of goggles  10  consists of refractive surfaces alternating with return surfaces. The inner optical array for the right lens  14  consists of refractive surfaces  600  that are generally flat and parallel with each other and are approximately parallel to the inner refractive surfaces  605  of the inner optical array of the left lens  13 . The outer refractive surfaces  610  on the right lens  14  are generally flat and also parallel with each other and are approximately parallel to the outer refractive surfaces  615  on the left lens  13 . The inner refractive surfaces  600 ,  605  are not necessarily parallel to the outer refractive surfaces  610 ,  615 . For example, as shown in lens  30  in  FIG. 8 , the outer refractive surfaces  31  are parallel to other outer refractive surfaces on each lens, but are not parallel to the inner refractive surfaces  32 . The left and right lenses also need not be mirror images of each other. The number of inner refractive surfaces does not need to be the same as the number of outer refractive surfaces of the lens. 
     Rays, for example  640  and  650 , observed by the swimmer both underwater and above water pass through the refractive surfaces  610  and  600 , and  615  and  605  respectively. Two rays that are parallel with each other before passing through the goggle lenses are also parallel with each other after passing through the lenses. This is true both for rays coming from straight ahead such as  640  and  650 , and for rays coming from the side, as depicted by  770  and  780  in  FIG. 7 . The optical rays  770  and  780  are shown in  FIG. 7  with underwater refraction angles. The direction cosine of a ray may change after passing through a lens of the goggles. However, the change in the direction cosine will be approximately the same for an optical ray that will be entering the left lens as for a ray that will be entering the right lens if these two rays are parallel to each other before they enter the lenses. Parallel rays remain parallel after passing through the lenses of these goggles. This is true when the parallel rays are either both underwater or both above water. 
     Referring to  FIG. 5-7 , the size of the outer refractive surfaces  615  and the size of the outer return surfaces  625  may be reduced while the number of such surfaces is increased to ensure that the maximum distance between any point on the outer surface and a specified profile  660  is arbitrarily small. Any profile, for example profile  660 , may be approximated to any degree of accuracy using only flat and parallel refractive surfaces  615  connected by return surfaces  625 . 
     Referring to  FIG. 11 . This figure illustrates nomenclature. Shown is a ray  1140  entering the outer lens surface  1100  of a portion of a lens. The normal  1160  to the outer surface  1100  at the point that ray  1140  enters the outer lens surface is shown. After refracting at the outer lens surface  1100  the ray, now labeled as  1130 , passes through the lens. After being refracted at the inner lens surface  1110  the ray, now labeled as  1120 , is shown on a trajectory to intersect the center of rotation  1180  of the eye. Also shown is the normal  1150  to the inner refractive surface  1110  at the point the ray  1120  exits the inner refractive surface. For simplicity of illustration, details of the cornea and eye lens structures are not shown; the eye including the cornea and eye lens are shown contained within a portion of a sphere. Optical rays of interest will always be assumed to start at an object, enter the outer surface of a lens, pass through the lens, exit the inner surface of the lens, and then enter the eye. 
     Flat and parallel refractive lens surfaces are one embodiment. A more general embodiment that also provides for standard vision goggle lenses is illustrated by referring to  FIG. 12 . For two parallel rays  1245  and  1240  that refract at the left  1205  and right  1200  outer surfaces of the left and right lenses respectively with the left ray, now labeled as  1295 , passing through the left lens section and the right ray, now labeled as  1290 , passing through the right lens section, and the left ray  1295  refracting at the inner surface  1215  of the left lens and the right ray  1290  refracting at the inner surface  1210  of the right lens, with the left ray, now labeled as  1225 , shown as the ray that is on a trajectory to intersect the center of rotation  1285  of the left eye and the right ray, now labeled as  1220 , shown as the ray that is on a trajectory to intersect the center of rotation  1280  of the right eye. After the two parallel rays  1245  and  1240  pass through the lenses and exit as rays  1225  and  1220  respectively two constraints assure that rays  1225  and  1220  are parallel. Firstly, that the normals to the outer lens surfaces  1265  and  1260  are parallel to each other and secondly that the normals to the inner lens surfaces  1255  and  1250  are parallel to each other. This assures standard vision both above and below the surface of the water when the left and right lenses of the goggles are both underwater or are both above water. 
     Another special case of the parallel normal constraint assuring standard vision is illustrated by  FIG. 9 . In this example, the refractive surfaces are sections of approximately spherical lenses with the center of curvature of the spherical surfaces approximately at the center of rotation of each eye. Here the right lens normals at the points of intersection are not just parallel with the respective left lens normals at the points of intersection. Here the lens normals at the points of intersection are also coincident with the respective rays. 
     The optical arrays as described in the instant invention with respect to the goggle embodiments of  FIG. 5-12  exhibit several characteristics. Each optical array has at least two refractive surfaces. The change in direction of a ray crossing through a refractive surface may be zero degrees such as when a ray is normal to the refractive surface. See for example  FIG. 9 . Refractive surfaces are smooth or piecewise smooth, but not necessarily flat. Refractive surfaces are regions of the goggles through which visual images are observed. Adjacent refractive surfaces may be connected by return surfaces or may abut one another. The refractive surfaces of these optical arrays differ from two transparent sections of goggles which are adjacent to each other in the prior art in two ways. Firstly, at least two adjacent refractive surfaces are connected by a return surface. Secondly, for two parallel rays passing through the left and right lenses which are then on trajectories to intersect with the centers of rotation of the left and right eyes respectively, the normals to the outer surfaces of the lenses at the points of entry of the respective rays with the left and right outer lens surfaces differ by less than 15 degrees, and preferably by less than 5 degrees. Thirdly, for two parallel rays passing through the left and right lenses which are then on trajectories to intersect with the centers of rotation of the left and right eyes respectively, the normals to the inner surfaces of the lenses at the points of exit of the respective rays with the left and right inner lens surfaces differ by less than 15 degrees, and preferable by less than 5 degrees. The center of rotation  685  of the left eye and the center of rotation  680  of the right eye are shown in  FIGS. 5-7 . The center of rotation  885  of the left eye is shown in  FIG. 8 . The center of rotation  985  of the left eye and the center of rotation  980  of the right eye are shown in  FIG. 9 . 
     Referring to  FIG. 13 ,  1310  is a contour line through a hydrodynamically streamlined profile.  1320  is a contour line through another useful profile. This profile represented by contour line  1320  will increase drag, but will also increase the inward hydrodynamical force applied to the lenses. This helps keep the goggles in the correct position particularly during a diving entry. The profile illustrated by contour line  1320  does not present corners that stick out into the free stream such as those exhibited by the 4,051,557 goggles, for example, as shown in prior art goggles of  FIG. 3 . 
     Pressure profile devices such as spoilers, airfoils, hydrofoils, flaps, and slats can be appended to the goggle profile to help provide retention of the goggles to the head. 
     For ease of plastic injection molding these goggles may be configured to provide for an approximately uniformly thick lens section. 
     The refractive surfaces  600 ,  610  may vary in shape. For example, refractive surfaces  43 ,  44  may have hexagonal or other shapes as shown in  FIG. 10 . 
     Optically blackening, opaquing or dulling one or more of the return surfaces  620 ,  630 ,  625 , and  635  may generate less glare for the swimmer. Blackening or dulling the return surfaces does not restrict the region of view. It only reduces the glare within the region of view. 
     The techniques disclosed in the instant invention are most useful for the region of binocular vision. For peripheral vision outside of the binocular region simple curved sections of clear material that match the desired outer profile may be acceptable. For many people the limits of binocular vision is about 30 degrees to each side. 
     Lenses of the present invention may be fabricated from clear or tinted plastic or from clear or tinted glass. Examples of suitable plastics include polycarbonate and acrylic. Eye seals or eye cups may be fabricated from an elastomer, an elastomeric foam, or soft plastic that minimizes leakage of water into the area adjacent to the eyes. Six materials commonly used for this purpose are chloroprene rubber, chloroprene foam rubber, EPDM, EPDM foam rubber, silicone rubber, and plasticized PVC. 
     Fabrication and sealing techniques known to those skilled in the art may be used to fabricate a complete set of goggles including a bridge connecting the left and right lenses together and an elastomeric head strap for holding the goggles to the head. Commonly used materials for bridges are polyethylene, polypropylene, polybutylene, acrylic, polycarbonate, polyurethane, plasticized PVC, or elastomers such as silicone rubber, natural rubber, chloroprene rubber, or EPDM. Head straps are commonly constructed from elastomers such as natural rubber including natural latex rubber, chloroprene rubber, EPDM, silicone rubber, or thermoplastic polymers such as polyurethane or plasticized PVC. 
     As many changes are possible to the swimming goggle and lens embodiments of this invention, utilizing the teachings thereof, the description above and the accompanying drawings should be interpreted in the illustrative and not in the limited sense.