This application claims domestic priority from US provisional patent application serial number 61/722,654 filed November 5, 2012. Background of the Invention

This invention relates to systems for functionally connecting optical filters to cameras used in hostile environments..

Photographic cameras designed for use in relatively extreme activities and hostile environments such as skiing, scuba diving and the like have become popular. A number of such cameras are offered by Woodman Labs, Inc. of Half Moon Bay, California in association with the trademark GoPro.

For above water applications, the benefits of mounting filters to a video camera are numerous. Examples include circular polarizers which reduce glare; especially in shots just above the surface of water (i.e. wake boarding, surfing or fishing). Circular polarizers are used to increase the contrast between the sky and clouds. Neutral density filters slow shutter speed thereby reducing the "jello effect" in high vibration environments or "prop blur" in aviation applications. Macro filters magnify and allow for focus on close-up items.

When used in underwater scuba diving activities, a GoPro or other hostile-environment camera must be mounted within a waterproof pressure tight housing. Manual controls such as the shutter release and others extend from actuators on the outside of the housing to the normal controls provided on the camera body located inside the housing. An optically clear path between the camera lens within the housing and the water and subject to be photographed outside the housing must be provided, of course.

Experienced scuba diver/underwater photographers know that the water they are diving in acts as a light color filter. Objects which appear to be red colored above water will appear to have little or no red color when they are located and observed at, for example, 10 or 15 feet below the surface of the water. As the divers and cameras go deeper into the water, other colors

progressively disappear. To obtain photographs of objects which appear to be normally colored, it is helpful to provide the underwater camera system with a color correction filter. One such filter is available from UR/PRO filters of Naperville Illinois, and is described and claimed in US patent 4,542,959.

A general object of this invention is to provide a filter mounting device or system which permits filters of virtually any kind or size to be quickly and securely mounted and demounted on cameras and camera housings for use in hostile environments.

A more specific object of this invention is to provide a filter mounting system for underwater photography in which the camera is safely mounted within a watertight and pressure tight housing, but in which the optical filter is mounted outside the housing so that the filter can be installed, removed, and changed for another filter while the system and user are underwater.

A related object is to provide such a system which permits filter attachment, removal and manipulation by a camera operator wearing relatively thick gloves in cold water or other environmentally hostile conditions.

Another object is to provide such a system which permits the system user to mount a wide variety of types, kinds and sizes of filters to the housing.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings. Throughout the drawings, like reference numerals refer to like parts.

Summary of the Invention In accordance with these objects, an optical filter mount and adapter is provided. This adapter comprises a proximate attachment mechanism adapted for snug fit and rigid attachment to a member associated with the camera. Here, the member is a faceplate frame affixed to the outside of the camera housing. A mediate member is rigidly affixed to the attachment mechanism, and a distal filter attachment member is affixed to the mediate member. This distal filter attachment member receives and rigidly mounts an optical filter in a position to pass light from an outside light source through the filter to a camera lens.

Brief Description of the Drawings Figure 1 is a view in partial section of the adapter for attaching an optical filter to a camera housing.

Figure 2 is a plan view of the adapter showing the front of the adapter.

Figure 3 is a plan view of the adapter similar to figure 2 but showing the rear of the adapter. Figure 4 is a side elevational view of the adapter. Figure 5 is a sectional view taken substantially in the plane of line 5— 5 in figure 2.

Figure 6 is an isometric view of the adapter.

Figure 7 is an exploded view of the adapter and the camera housing to which the adapter can be attached. Figure 8 is an isometric view of the camera housing showing the adapter attached to that housing.

Figure 9 is a front plan view of a second embodiment of the novel adapter.

Figure 10 is a rear plan view of the novel adapter shown in figure 9.

Figure 11 is a side elevational view of the novel adapter shown in figures 9 and 10. Figure 12 is an isometric view of the front of the adapter shown in figures 9, 10 and 11 and further illustrating the placement of an optical filter on and in the adapter.

Figure 13 is a rear isometric view of the novel adapter shown in figures 9-12.

Figure 14 is a sectional view taken substantially in the plane of 14 - 14 in figure 9.

Figure 15 is a sectional view taken substantially in the plane of line 15 - 15 in figure 10. Figure 16 is an isometric view of a camera housing, an optical filter, and the adapter device connecting the optical filter to the camera housing.

Figure 17 is an exploded view illustrating the mechanism and the method by which the adapter is attached to the camera housing faceplate. Figure 18 is a sectional view of the adapter showing the placement of O-ring sealing devices in the adapter.

Detailed Description

While the invention will be described in connection with several preferred embodiments, it will be understood that it is not intended to limit the invention to these embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention.

As shown in the drawings, one aspect of the invention provides an adapter 20 for attaching an optical filter 22 to the outside of a camera housing 50. As shown particularly in figures 1-7, this adapter 20 includes a proximate attachment mechanism 24 adapted for rigid attachment to a faceplate member 54 associated with the camera housing 50. Here this faceplate member 54 comprises a faceplate frame 56 which mounts a transparent faceplate 58. That transparent faceplate 58 is positioned over the lens of a camera (not shown) secured within the underwater housing 50. A mediate member 26 is rigidly affixed to the attachment mechanism 24. This mediate member 26 can be a hollow toroid to permit light to pass from a camera filter 22 through the adapter 20 and into the camera housing 50 and then to the camera lens.

A distal filter attachment member 28 is affixed to the mediate member 26. It is adapted to receive and rigidly mount an optical filter 22 in a position to pass light from an outside light source through the filter 22 to the camera lens. This filter attachment member 28 can be provided with threads 32 to accept filters of standard sizes and thread pitch. Here the threads are formed to accept a standard, off-the-shelf 55 mm diameter filter, but camera filters of any other size or shape, either standard or nonstandard, can be accepted by suitable modification of the adapter 20.

In accordance with one aspect of the invention, the adapter 20 includes faceplate attachment means 36 for attaching the adapter 20 and any optical filter 22 mounted thereto to the camera housing 50 and, more specifically, to the faceplate frame 54. As shown especially in figure 7, the frame 54 is rectilinear in shape. A rectilinear collar 38 on the mediate member 26 fits over and around the faceplate frame 54. In accordance with one aspect of the invention, mounting devices 42, 44 are located in generally opposed positions as shown in figure 7 so as to engage the face plate frame 54. Connectors or clips 46, 48 extend inwardly from these mounts 42, 44 into one or more faceplate frame grooves 60 as shown especially in figures 1 and 7.

To fit the adapter 20 to the faceplate frame 54, the collar 38 of the proximate attachment member 24 is sized to fit snugly around the faceplate frame 54, and to align the faceplate surface 64 with the inner surface of the filter 22 which has been screwed snugly into the distal filter attachment member 32.

In an alternate embodiment of the invention, threaded fasteners such as bolts or screws (not shown) can be provided to extend through the distal filter attachment member. As these fasteners are tightened, the filter 22 and filter attachment device 20 are drawn into snug engagement with the faceplate frame 54. Other known attachment means can be used.

A second embodiment of the invention is shown in Figs. 9-18. When the novel adapter and camera filter are assembled to the camera housing, an empty space 70 is provided. This empty space can be sealed by O rings 72, 74. In accordance with another aspect of the invention, the adapter 20 can be attached to the camera housing 50 when the adapter and camera are underwater. Under these circumstances, this empty space 70 will be pressure tight and will be filled with water. When the adapter 20 is attached to the camera housing 50 under these circumstances, camera faceplate fogging and optical filter fogging are prevented. Trapped air bubbles formed inside the space 70 can be easily eliminated before filter attachment to the camera housing by simply shaking or rubbing the attachment device 20 before attaching it to the faceplate. Alternatively, the empty space 70 can be filled with a fluid such as isopropyl alcohol. The isopropyl alcohol will prevent fogging, and, in addition, the isopropyl alcohol will not freeze during use in cold climates.

In another embodiment of the invention, the novel adapter may include a feature that allows moisture absorbing material such as desiccant or activated alumina to be held securely in the sealed space between the filter and camera or camera housing created by the adapter in order to prevent moisture condensation in this airspace. Known means for mounting a desiccant holder can be provided in this space 70. When used without one of the O-rings, the adapter 20 acts as a "wet filter" adapter. Holes at the top and bottom of the unit allow the space between the filter and housing to flood easily. This configuration is commonly used during scuba dives where a color-correction filter is used. The adapter can be easily installed and removed during the dive as the water depth and lighting conditions change. For example, the filter can be removed at shallow depths or when lights are turned on in close proximity to a coral bud. The unsealed configuration is also the easiest to use on land when rain, mud, or snow intrusion is not probable.

In environments where rain, mud, or snow may be forced between the filter and the camera housing it is best to seal the space between the housing and the filter. Installing the correct size O-ring between the filter and the adapter makes sealing this space easy to do. Capturing air between the filter and adapter is the simplest approach in most environments. Having an airtight seal also makes it difficult to remove the adapter due to pneumatic effects. The downside to trapping air in the space between the filter and the housing is humidity in the air will condense and fog if rapid temperature changes occur. To avoid fogging, it may be advisable to allow the camera, adapter, and filter to sit in the intended use environment before seating the filter against the O-ring. For example, installing the filter in the ski lodge before going skiing will likely result in fogging. Instead, it is preferable to install the filter after getting off the ski lift - when everything is cold.

Persons participating in snow sports, surfing, fishing, cliff diving - any situation where moisture may creep behind the filter during above water shots - will all benefit from the ability to seal the space behind the filter. Any below water to above water transition will be cleaner with a sealed unit since water is not going to be trapped behind the filter.

Trapping liquid between the filter and housing is also an option. This configuration makes the adapter impossible to pull off since it is held on by hydraulic pressure - liquid does not compress under pressure. This configuration is an excellent for surfers as water is readily available and fogging is not an issue with a fluid filled space. Water is not a good fluid to use during snow sports since it will most likely freeze. Alcohol can be substituted to prevent freezing but installation using alcohol may require the unit to be submerged and all air bubbles shaken out before sealing the unit. This adapter 20 can be attached to the camera housing 50 by pressing, slipping or sliding the adapter over the camera faceplate frame. This attachment can be accomplished virtually any time, anywhere and under any conditions. The filter can thus be attached underwater, or in snow or cold or in any other environment where the camera user may find him or herself. By appropriate modification of the proximal element 28, this filter attachment device 20 can be used with other extreme sports or action cameras.

By other modifications of the proximal element 28, this filter attachment device 20 can be attached directly to an unhoused camera or camera lens itself.