Depth-compensated underwater light

[0003] The invention relates generally to self-contained lights, and more particularly to a depth-compensated underwater light that can be made from non-magnetic components if necessary.

[0004] Underwater divers frequently need to check display readings on a variety of equipment such as the diver's underwater breathing apparatus or sensors being carried by the diver. In low-light conditions, these displays can be difficult or impossible to read. Accordingly, the ability to illuminate the display becomes a requirement. Currently, divers use chemical lights that illuminate when mechanically manipulated to allow chemicals contained therein to mix/react to generate luminescence. These lights are continuously “on” once activated. However, in many military applications such as mine clearing operations, lighting of the display must be brief in order to minimize the chance of detection from the water's surface. Further, since mine clearing operations could be compromised by the presence of magnetic material, all equipment carried by the diver should present little or no magnetic signature.

[0005] Accordingly, it is an object of the present invention to provide light for use in underwater applications.

[0006] Another object of the present invention is to provide underwater light constructed for depth compensation.

[0007] Still another object of the present invention is to provide an underwater light having little or no magnetic signature.

[0008] Yet another object of the present invention is to provide an underwater light that can be turned on and off easily.

[0009] Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings.

[0010] In accordance with the present invention, an underwater light includes a sealed housing defined by a rigid portion and a flexible portion. The rigid portion incorporates a window for permitting the passage of light therethrough. A light source is mounted in the housing to direct light generated thereby through the housing's window. A power source is also mounted in the housing. An open electrical circuit couples the power source to the light source. The open electrical circuit includes spaced-apart terminals that prevent electrical power generated by the power source from being delivered to the light source. One of the terminals is coupled to the flexible portion of the housing and is aligned with another of terminals. Flexing of the housing's flexible portion into the housing causes the terminals to contact one another so that electrical power can be delivered to the light source. For depth compensation, a non-compressible dielectric fluid fills the housing.

[0011] Other objects, features and advantages of the present invention will become apparent upon reference to the following description of the preferred embodiments and to the drawings, wherein corresponding reference characters indicate corresponding parts throughout the several views of the drawings and wherein:

[0012] FIG. 1 is an exploded perspective view of the components in one embodiment of the underwater depth-compensated light in accordance with the present invention;

[0013] FIG. 2A is a perspective view of the display assembly used by U.S. Navy's Mk16 underwater breathing apparatus;

[0014] FIG. 2B is a side view of the display assembly taken along line 2—2 in FIG. 2A; and

[0015] FIG. 3 is a side cross-sectional view illustrating only the present invention's rigid housing and flexible lid sealed together to illustrate the void formed therebetween.

[0016] Referring now to the drawings, and more particularly to FIG. 1, an exploded view of one embodiment of an underwater depth-compensated light according to the present invention is shown and referenced generally by numeral 10. Underwater light 10 will be described for its use in conjunction with the U.S. Navy's Mk16 underwater breathing apparatus (UBA) which will be described briefly using FIGS. 2A and 2B. However, it is to be understood that the underlying principles of the light described herein can be applied in a variety of embodiments without departing from the scope of the present invention.

[0017] In FIGS. 2A and 2B, a display assembly used by the Mkl6 UBA is shown in perspective (FIG. 2A) and side (FIG. 2B) views, and is referenced generally by numeral 100. In relevant portion, display assembly 100 includes a housing 102 supporting a display screen 104 protected by a display glass 106. To provide for the illumination of display 104, a hole 108 is formed in the side of housing 102 to provide access to display screen 104 and display glass 106 as best illustrated in FIG. 2B. A rubber boot 110 (used to previously house a now obsolete piece of equipment) is coupled to housing 102. An opening 112 is formed in boot 110 to receive underwater light 10 therein where the light generated thereby is focused through hole 108 to illuminate display screen 104.

[0018] Reference will now be made to FIGS. 1 and 3 simultaneously where FIG. 3 illustrates only the outer structure of light 10. Underwater light 10 includes an open, cylindrical rigid support housing 12 having therein a plurality of mounting ribs 14 and locating pegs 16 for supporting the mounting of components thereon as would be well understood in the art. The particular design of the mounting assembly defined by ribs 14 and pegs 16 is merely representative and is not to be considered a limitation of the present invention. In the illustrated embodiment, housing 12 is sized/shaped for a compression fit with opening 112 in boot 110 so that light 10 and boot 110 are sealed to one another.

[0019] Housing 12 further defines a light mounting 18 for receiving therein a light 30 such as an LED. Light mounting 18 serves as a mechanical locator and attachment point for light 30. As best seen in FIG. 3, light mounting 18 terminates in a transparent window or lens 18A through which light can be transmitted. Light mounting 18 and window 18A are positioned for correspondence with hole 108 in housing 102. Window 18A can be sized to fit into hole 108 and, therefore, can be made to extend axially from housing 12. A fill hole 20 is provided in housing 12 to permit the filling of underwater light 10 with a non-compressible fluid 42 as will be explained further below. Once filled, hole 20 is sealed with a plug 22.

[0020] Light 30 has its leads 30A and 30B electrically coupled to an open circuit arrangement defined by one or more batteries 32 (e.g., “credit card” type lithium batteries), an electrical contact 34 and leads electrically linking light 30, batteries 32 and contact 34 as shown by dashed lines 36. Note that if lithium batteries are used, a high-ohm resistor (not shown) can be placed across the battery terminals to prevent development of a passivation layer on the batteries as is known in the art. Contact 34 is securely mounted in a receptacle 38A formed in a flexible lid 38.

[0021] During assembly, light 30, batteries 32 and contact 34 are electrically coupled by leads 30A and 30B as described above. Light 30 and batteries 32 are mounted in housing 12 and contact 34 is mounted in receptacle 38A. Housing 12 and flexible lid 38 are sealed to one another (e.g., bonded, welded, fused, etc.) at their respective outer peripheries to form an internal void 40 (illustrated in FIG. 3) housing the components described above. Void 40 is then filled with a non-compressible dielectric fluid 42 via fill hole 20, and hole 20 is sealed by plug 22. Flexible lid 38 is constructed with receptacle 38A positioned such that contact 34 and one negative terminal 32A of one of batteries 32 are maintained in a spaced-apart relationship after light 10 is assembled thereby essentially defining terminals of an open electrical circuit.

[0022] Flexible lid 38 forms a flexible diaphragm sealed to housing 12 and forms the activating “button” for underwater light 10. That is, from an electrical perspective, when a force is applied to flexible lid 38 such that it is pressed/flexed into void 40 until contact 34 touches terminal 32A, a closed electrical circuit is formed so that power from batteries 32 is supplied to light 30. When the force is removed, flexible lid 38 returns to its at rest condition to thereby define an open circuit once again. Thus, underwater light 10 is only on when flexible lid 38 is pressed/flexed into void 40.

[0023] Since underwater light 10 will be subject to depth pressures, pressure compensation is required to prevent flexible lid 38 from flexing into void 40 (and activating light 30) as depth pressure increases. Accordingly, as described above, void 40 is filled with non-compressible dielectric fluid 42 (via fill hole 20) after all electrical components are mounted therein and flexible lid 38 is sealed to housing 12. Such non-compressible fluids are known in the art and could include, for example, silicone-based gels or oils and synthetic transformer oils.

[0024] The volume of underwater light 10 cannot change when flexible lid 38 is pressed into void 40. Since housing 12 is rigid, flexible lid 38 must flex to allow non-compressible fluid 42 to redistribute itself when light 10 is activated. To facilitate volume redistribution of fluid 42, flexible lid 38 can incorporate a plurality of concentric ridges 38B.

[0025] As mentioned above, light mounting 18 in housing 12 incorporates a transparent window 18A. While this could be a separate component, housing 12 could also be made entirely from a transparent plastic thereby integrating window 18A directly into housing 12. If constructed in this fashion, it would be preferable to construct flexible lid 38 to be optically opaque to prevent light (generated by light 30) transmission back through flexible lid 38.

[0026] Although housing 12 is rigid and lid 38 is flexible, they can be made from the same material to facilitate the seal that must be formed therebetween during construction as like materials are more easily joined to one another. Rigidness/flexibility of housing 12 and lid 38 can be adjusted by the thickness thereof and/or the use of flexibility enhancing structure such as concentric ridges 38B. Typically, housing 12 and lid 38 are made from a plastic material having high elongation and low tensile strength.

[0027] If underwater light 10 is to present little or no magnetic signature, all components thereof should be substantially non-magnetic. For example, housing 12 and lid 38 can be plastic. Batteries 32 can be lithium batteries. Contact 34 can be made from brass. Light 30 and electrical leads 36 can all be selected to have little or no magnetic signatures. In this way, underwater light 10 can be safely used in mine clearing operations or around any equipment (e.g., a compass) that would be affected by the presence of a magnetic signature.

[0028] The advantages of the present invention are numerous. An underwater light of simple construction and operation will provide a diver with light on demand. Since the light is only activated when needed, its life will be extended as it cannot remain activated inadvertently. The light is pressure compensated so that it will be unaffected by increasing/decreasing depth pressure. Further, in illustrated embodiment, the present invention will find immediate utility with the display on the U.S. Navy's Mk16 UBA.

[0029] Although the invention has been described relative to a specific embodiment thereof, there are numerous variations and modifications that will be readily apparent to those skilled in the art in light of the above teachings. For example, the particular light, power source and/or arrangement for the open electrical circuit coupling the light and power source, are not limited to the illustrated embodiment. More or less batteries, or different types thereof, could be used as required. The rigid housing and flexible lid could be constructed other than as shown and in different shapes to suit a particular application. For example, either the rigid housing or flexible lid could be formed as a hand-held body. In the former case, the flexible lid would be formed as a depressible button whereas in the latter case the flexible lid could be squeezed by one's hand. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described.