Diving mask having distortionless peripheral vision

A diving mask comprising a supporting member for sealing engagement with the face of the user, a lens mounted in the supporting member near the eyes of the user to provide a low volume mask, a major portion of the lens being curved so that apparent magnification of images underwater is less than that observed through a conventional flat lens plate, certain portions of the lens being further curved to eliminate or mitigate pincushion-type distortion.

BACKGROUND OF THE INVENTION 
Prior art attempts to make diving masks are best represented in U.S. Pat. 
Nos. 3,055,256 issued Sep. 25, 1962 to John H. Andresen, Jr., U.S. Pat. 
No. 3,672,750 issued Jun. 27, 1972 to Kenneth G. Hagen and U.S. Pat. No. 
3,320,018 issued May 16, 1967 to Max H. Pepke. The Andresen '256 patent 
discloses a mask for divers with imperfect vision which includes a 
conventional mask frame in which is mounted a spherical lens. The Hagen 
'750 patent discloses a diving mask with curved lenses for each eye, with 
a center of curvature for each lens at the eyeball of the user. The Hagen 
mask should be custom made for each user to locate the specific eye points 
(e.g. optical centers and eye depth) properly; a universally acceptable 
mask simply cannot be made according to the teachings of Hagen. Further, 
it has been found that only slight shifting of the Hagen mask on the 
user's face distorts one's vision to such an extent that nausea may 
result. Obviously then, such a diving mask is fundamentally unacceptable. 
Pepke '018 is relevant at FIG. 20, showing a diving mask, again with 
spherical lenses having separate centers of curvature but located at the 
pupils of the eyes of the user, rather than at the centers of the 
eyeballs. The Pepke mask suffers the same deficiencies as Hagen's; the 
teachings of the Pepke patent cannot be used to produce a universally 
acceptable, distortionless vision mask but only individual masks, custom 
made for each category of diver user. 
Remaining prior art disclosures are remote. U.S. Pat. No. 2,876,766 issued 
Mar. 10, 1959 to Dimitri Rebikoff et al and U.S. Pat. No. 3,010,108 issued 
Nov. 28, 1961 to Melvin H. Sachs illustrate diving mask lenses curved 
laterally and vertically. However, neither patent even remotely suggests a 
mask lens curvature specifically designed and configured to provide 
distortionless vision underwater. The distortions inherent in such 
unspecified curvatures have also been found to dangerously cause nausea to 
users. U.S. Pat. No. 2,952,853 issued Sep. 20, 1960 to Howard a Benzel and 
U.S. Pat. No. 3,027,562 issued Apr. 3, 1962 to James K. Widenor are more 
remote and simply show diving masks curved in a plane only; vision 
distortion is only exacerbated by such a construction, not alleviated. 
U.S. Pat. No. 3,483,569 issued to Israel Armendariz is similar. Again, the 
safety-threatening condition of a diver nausea is inherent in these 
designs. 
More exotic disclosures of attempts to provide magnification-free 
underwater vision are provided by U.S. Pat. Nos. 3,040,616, issued Jun. 
26, 1962 to George R. Simpson and U.S. Pat. No. 4,373,788 issued Feb. 15, 
1983 to M. Linton Herbert. These patents disclose dual focal point lenses 
structures with air chambers behind the lenses in the former patent and a 
filling and draining bladder structure in the latter to permit 
readjustment of several lenses. Clearly, both designs are unfavorably 
complex and impractical. 
Other prior art disclosures directed to attempt to improve certain aspects 
of underwater vision and/or provide diving mask myopia-correction lenses 
include U.S. Pat. No. 2,928,097 issued Mar. 15, 1960 to Lester M. Neufeld, 
U.S. Pat. No. 3,051,957 issued Sep. 4, 1962 to Chester C. Chan and French 
Pat. No. 1,374,010 issued Aug. 24, 1964 to Jean-Louis Marro and an article 
entitled Visual Problems of Skin Diving by James R. Gregg, Skin Diver 
Magazine, April 1961, reprinted in The Optometric Weekly, Jul. 13, 1961 pp 
1381-1388. 
What the prior art fails to disclose is a diving mask having a lens 
configured to provide substantially distortion-free underwater vision, a 
major portion of the mask lens being curved so that the apparent 
magnification of images underwater is less than that observed through a 
conventional, flat lens plate, certain portions of the lens being further 
curved to eliminate or mitigate pincushion-type distortion. 
OBJECTS AND SUMMARY OF THE INVENTION 
Accordingly, it is a principal object of the invention to provide an 
enhanced peripheral vision mask or other underwater vision device having a 
faceplate lens major surface created from a specified aspherical, an 
ellipsoid or a paraboloid configuration to improve underwater vision by 
reducing pincushion-type or barrel-type distortion and magnification. 
It is a further object of the invention to provide a low volume, enhanced 
peripheral vision mask created from the combination of a narrow skirt 
which allows a portion of the user's nose to extend forwardly of a 
faceplate lens major surface created from a sphere configuration. 
It is another object of the invention to provide a diving mask having a 
faceplate lens curved in a predetermined manner so that vision underwater 
appears to be more closely similar to vision in air. 
It is a further object of the invention to provide a diving mask having a 
faceplate lens of simplified, uncomplicated structure which is low in cost 
of manufacture yet provides substantially distortion-free underwater 
vision. 
It is yet a further object of the invention to provide an uncomplicated and 
substantially distortion-free magnifying diving mask.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings by reference character, and particularly 
FIGS. 1 and 2 thereof, an embodiment of the invention is shown including a 
simple faceplate lens 10 carried by a thin profile surrounding skirt 12. 
The low profile of skirt 12, with a portion of the user's nose extending 
forwardly of the lens, combined with curved faceplate lens 10 provides a 
streamlined mask of low internal volume. Also, the construction permits 
the lens 10 to be as close to the face and eyes of the user as comfort and 
practically will permit, so that peripheral vision is further enhanced in 
part by expected mathematical effect. In the case of simple spherical 
lenses, however, there is noted an additional further, unexpected, 
disproportionate, geometrically synergistic effect which plays an extended 
role of enhancing peripheral vision beyond the relevant prior art 
teachings. 
Faceplate lens 10 may be made from material generated from any one of a 
wide variety of geometric shapes. Unlike prior art faceplate lenses, it 
has been found possible to create a lens which is virtually 
distortion-free and substantially devoid of pincushion-type or barrel-type 
distortion. Pincushion distortion occurs as the field of vision is viewed 
anywhere except generally straight ahead and increases as the field is 
viewed farther and farther from straight ahead. For example, parallel 
straight lines, horizontal and vertical, appear to acquire increasingly 
more distance between them with increasing distance from the field of 
view's central portion. 
It has long been desired to create an acceptable diving mask wherein vision 
underwater appears the same as unobstructed in air, in other words, a mask 
having a lens that reduces the magnifying effect of water viewed through 
the air inside the mask and at the same time provides continuous and truly 
substantial peripheral vision. 
With reference to FIG. 3, I have found that a suitable mask can be made by 
combining a narrow supporting skirt which positions the lens so that a 
portion of the user's nose extends forwardly from the lens, with a lens of 
transparent material created from a spherical surface. Thus, a lens 14, is 
shown having a single radius of curvature across the entire surface 
thereof, the center of curvature of the sphere being well behind the 
eyeballs of the user. This lens, in combination with the aforementioned 
new positioning is in direct contradistinction to prior art diving masks 
which are intended to eliminate the visual magnification present by being 
underwater, such masks teaching either dual curved lenses having centers 
of curvature at the centers of the user's eyeballs or at the user's 
pupils, or in another example the single curved lens failing to be 
combined with the peripheral-vision-enhancing positioning described above, 
which produces an unexpected, disproportionate and synergistic geometrical 
effect. In a preferred embodiment, the radius of curvature of the sphere 
16 will be in a range of from five to about seventeen inches or more and, 
more preferably, on the order of about nine-to-twelve inches. This 
provides a diving mask lens wherein the user appears to see objects 
underwater much the same as he would in air, without the typical 
magnification created by the fact that the index of refraction of water is 
about 1.33 Whereas that of air is 1. 
FIGS. 4A and 4B illustrate such a lens 14 in horizontal and vertical 
cross-section. 
FIGS. 5A and 5B, similar to FIGS. 4A and 4B, illustrate an even more 
satisfactory lens surface 18 wherein, for example, a central, major 
portion 20 is spherical and the outer, upper and lower edges become 
specified aspherical or ellipsoidal in configuration as is indicated at 
22. This more pronounced curvature at portions 22 assists in reducing the 
pincushion-type distortion phenomenon discussed above. These views also 
illustrate that the lens 20 could alternatively be generated as an 
aspherical surface of specified, incrementally decreasing radii beginning 
from a center axis or center point or points, the latter of which is 
illustrated in dotted lines in FIG. 5A. 
FIGS. 6A and 6B, similar to FIGS. 4A and 4B, show a lens 24 generated from 
an ellipsoidal surface; such a lens also assists in reducing the 
pincushion distortion phenomenon. These views also illustrate that the 
lens 24 could alternatively be generated as an aspherical surface of 
specified, incrementally decreasing radii, beginning from a center axis 26 
or central point or points, the latter of which is illustrated in dotted 
lines in FIG. 6A. In any event, pincushion distortion is reduced in lenses 
20 and 24 because the angles of incidence of incoming light rays, 
particularly from the direction of the more peripheral areas of the 
faceplate lens, are closer to being at right angles to tangents drawn at 
the lens surface than is the case with single-radius spherical lenses and 
conventional flat faceplate lenses of any readily available diving mask. 
Also, the outer areas of reduced radius provide a further reduced image 
size in those areas which effect appears to also contribute in reducing 
pincushion distortion. 
Turning now to FIGS. 8, 9 and 10, faceplate lenses generated from other 
geometric forms are illustrated. FIG. 8 illustrates a lens 28 generated 
from the surface of an ellipsoid 30 created by rotating an ellipse about 
its short axis 32. Here, it should be noted that the lens may be taken 
radially from the axial portion of ellipsoid 30 so that curvature of the 
lens away from its center axis (e.g., 32, FIG. 8) is uniform 
In FIG. 9 a lens 34 is generated from the surface of an ellipsoid 36 
created by rotating an ellipse about its long axis 38. In this case, the 
lens may be taken radially from the long rather than short axial portion 
of ellipsoid 36 as is roughly illustrated. 
In FIG. 10, the surface is a paraboloid 40 created by rotating a parabola 
about is axial centerline 42 and the lens 44 may be taken from the axial 
portion of paraboloid 40 as is roughly illustrated. 
FIG. 7 illustrates another embodiment of the invention comprising a pair of 
faceplate lenses 46, 48 mounted in a mask skirt 50. Preferably, lenses 46 
and 48 are generated from a continuous smooth curved surface as in the 
embodiments discussed above. For example, if generated by a spherical 
surface, lenses 46 and 48 will have the same radius of curvature and 
common center of curvature, somewhat behind the eyes of the user. If 
desired, lenses 46 and 48 could be displaced somewhat from a true 
imaginary common spherical surface so as to provide two distinct centers 
of curvature, one for each lens, but each well behind the eyes of the 
wearer. 
A magnifying diving mask 64 is illustrated in FIG. 11, including a 
faceplate lens 66 in a frame 68, which lens may be selected from any of 
the lenses of the previously described embodiments except spherical, but 
is mounted in reverse, so that the convex surface of lens 66 is adjacent 
the user's face, rather than the concave side as in the previous 
embodiments. Distortion can be eliminated or mitigated in this type of 
mask by selecting a lens which possesses multiple radii of curvature where 
the radii lengths generally increase with increasing distance away from a 
central point or points, as in a paraboloid, for instance. 
In all of the embodiments discussed, preferably the lens material is of 
uniform thickness but in certain applications it may be desirable to vary 
the material thickness and/or composition Also, it is desired that the 
lens structure be rather rigid so that predetermined visual properties of 
any selected lens are not varied or altered by bending, e.g., when a mask 
is placed on the face of the user. 
While the present invention has been shown and described as applied to a 
diving mask, it is to be understood that it may also be incorporated in a 
diving helmet, a full face diving mask, or other underwater vision device. 
While this invention has been described as having a preferred design, it is 
understood that it is capable of further modifications, uses and/or 
adaptations of the invention and following in general the principles of 
the invention and including such departure from the present disclosure as 
come within known or customary practice in the art to which the present 
invention pertains, and as may be applied to central features herein 
before set forth, and fall within the scope of the invention or the limits 
of the claims appended hereto.