Abstract:
A video fishing rod with underwater observation gear as fishing equipment, allowing surveillance of the bait and fish around it, and includes a video monitor attachable to the fishing pole, miniature submersible video camera attached close to the end of the fishing line for transmitting video images up to the monitor via the same fishing line without the use of a video cable.

Description:
BACKGROUND OF THE INVENTION 
     This invention is concerned with the recreational fishing equipment that enhances the pleasure of fishing by allowing a fisherman to see underwater space in the locality of the hook and bate. The devices known in the art that offer similar viewing are based on the use of sealed submersible video cameras attached to the end of a coaxial video cable. The cable transmits video signals from the camera to the video monitor placed near the fisherman. Such submersible video systems are especially popular among the ice fishing anglers as they help to realize better the situation under the ice, which blocks direct observations. Under water video cameras are also used on limited scale by professional fishermen to improve efficiency of fishing. There is some evidence of use the underwater video equipment by recreational anglers in warm waters of streams and rivers. U.S. Pat. Nos. 6,057,879, 6,784,920, 6,091,443, 6,262,761, 6,476,853 describe variations of the systems and equipment having in common a submersible video camera transmitting video signal to a monitor located above the water via a common video cable. All such systems have some drawbacks that this invention is destined to remove. One problem with the existing systems is that the actual use of them is quite cumbersome. Typically, the user needs to unwind or spread the video cable, connect the distal end of it to the camera, secure the proximal end to ensure the cable will not slip off in to the water, connect the cable to the monitor, and hookup the 12-volt battery. Then he would use two separate lines at the same time: the fishing line and the video cable line, which is much less flexible than the fishing line. The other problem with the existing systems is the relatively high cost of the small diameter coaxial cable. Children and retirees constitute the main part of population that engages in recreational fishing. The proposed invention allows the video capable fishing rod to be affordable to everybody, at the same time offering compactness and convenience of use. 
     SUMMARY OF THE INVENTION 
     The invention relates to a video fishing rod system comprising a fishing pole having a handle, a reel with a fiber optic fishing line, a sealed submersible video camera attached at the distal end of the fiber optic fishing line, a leader with a fishing hook attached proximate the video camera, a video display monitor with internal battery cells and attached to the fishing pole, typically near its handle, a miniature battery housed inside the submersible camera to power the imaging electronics and optic-electronic components, which provide communication between the video camera and the video display monitor via the fiber optic fishing line. 
     The fiber optic fishing line comprises an optical fiber or equivalent that replaces the conventional monofilament fishing line. Generally, the fiber-optic line comprises a colorless monofilament plastic fiber with a core having a first refractive index, and a clear cladding made of a plastic material with a second optical refractive index lower than the first refractive index. This condition allows efficient propagation of optical energy (that is, light signals) along the length of the fiber-optic line. Such optical fishing line does not look much different from a conventional monofilament fishing line. A fiber-optic line with the diameter from about 0.5 mm to about 1.0 mm has the strength and durability sufficient for its use as a monofilament fishing line. An additional top layer of protective plastic, such as polyurethane, vinyl or UV curable epoxy, improves resistance of the fiber-optic line to wear and tear. 
     The proposed invention utilizes a miniature submersible video camera positioned above or aside the baited fishing hook. The camera transmits live video images of the space in its field of view via the fiber-optic fishing line to the portable video monitor, typically a miniature LCD monitor, located near the person who is using the fishing pole (that is, an angler) or other observer. This arrangement allows recreational fishing to be a lot more fun and instructive. An angler can see the bait and monitor the process of a fish getting on the hook. Such compact, ready to use fishing gear is especially attractive to children and useful to ice-fishing, fresh water, and seawater anglers. 
     The invention also relates to underwater viewing system using the submersible video camera for general observation under water, without a fishing hook. The underwater viewing system comprises a pole having a handle, a reel with a fiber optic fishing line, a sealed submersible video camera with an imbedded LED illuminator and attached at the distal end of the fiber optic fishing line, a video display monitor attached to the pole, typically near its handle, one battery imbedded into the camera to power the imaging and optic-electronic components responsible for taking images and providing communication between the video camera and the video display monitor, and the other battery imbedded into the video monitor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates the complete video fishing rod system. 
         FIG. 2  shows the cross section of the submersible video camera attached to the distal end of the optical fishing line, and having a leader with the fishing hook attached to the front side of the camera. 
         FIG. 2   a  shows an enlarged portion of the  FIG. 2  drawing, illustrating the attachment of the optical line to the camera and its interaction with the optical transmitter. 
         FIG. 3  shows the cross section of the submersible video camera with the internal LED illuminating the scene. 
         FIG. 4  illustrates the bobbin on the reel that holds the optical fishing line. 
         FIG. 5  illustrates the cross section of the reel and the bobbin with the metal shaft of the reel. 
         FIG. 6  illustrates a cross section of the reel and the bobbin, without the metal shaft. 
         FIG. 7  shows a block diagram of the electronic components of the video fishing rod system. 
         FIG. 8  illustrates the use of the video camera in a horizontal orientation perpendicular to the descending optical fishing line. 
         FIG. 9  illustrates an alternative means for fastening of the video camera to the optical fishing line. 
         FIG. 10  illustrates the use of the submersible video camera without a fishing hook for general observation under water. 
         FIG. 11  illustrates an alternative means for fastening of the fishing hook to optical fishing line. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The video fishing rod system shown on the  FIG. 1  comprises a fishing pole  10  having a handle  1 . The video monitor  2  is attached to the fishing pole  10  just above the handle  1 . The reel  6  with the reel handle  7  is secured traditionally to the pole below the monitor  2 . The monitor  2  has a TFT LCD display  4 , a hood  5 , a brightness control and power switch  3 . The monitor also uses removable and replaceable battery cells as a power source, and not shown here for clarity. The fishing line  9  is a monofilament plastic fiber-optic line that is wound on the bobbin of the reel  6 . The fishing line is threaded through the supporting rings  8  attached to the elongated main body of the fishing pole  10 . At the distal end of the fishing line, a miniature color or monochrome video camera  11  based on a complementary metal oxide semiconductor (CMOS) image sensor is attached. A fishing hook  12  is attached to a front end of the camera through the leader line  14  and the leader support line  13 , as illustrated. 
       FIG. 2  and  FIG. 2   a  illustrate attachment of the submersible video camera  11  to the fiber optic fishing line  9 , and to the fishing hook  16 , respectively. The submersible video camera  11  is housed in a hermetically sealed cylindrical enclosure having a clear acrylic or glass window  32  at the front end (the bottom side as shown in  FIG. 2 ). The window  32  is integral with a cover ring  28 , which can be unscrewed to gain access for replacing the battery  25 . The battery  25  can be rechargeable or disposable. An optional power switch is also located inside the enclosure. The power converter  50  prepares the voltages needed for the electronics of the submersible camera. The CMOS color video device  26  with the imaging lens  30  is located near the front end of the interior of the housing  17  of the camera  11 . 
     The lens  30  with the viewing angle α delivers observation of a space surrounding the fishing hook  16 . The CMOS video device  26 , the battery  25  and the power converter  50  are mounted on the removable plate  27 . The flexible wire  24  connects the CMOS video device  26  with a transmitting means located at the back end (top side) of the housing  17 , for transmitting the video image signal from the video device  26 . The length of the flexible wire  24  allows the removable plate  27  to be pulled out of the front opening of the housing  17  far enough for replacing of the battery  25 . 
     The preferable type of the transmitting means is an analog transmitter with the amplitude modulation of the optical power (what optical power?). A digital transmitter is also acceptable especially if a very long, longer than 200 feet, optical fiber is considered. The digital transmitter will require using a corresponding digital receiver on the other end of the fiber, as discussed later. The analog transmitter is less expensive, and is conveniently used for the most popular uses of the invention. The transmitter comprises the LED  22  and the LED driver  23 . A semiconductor laser can be used in place of the LED if much longer optical fiber length is desired. An LED is less expensive yet suitable for fiber optic communications, and can be used successfully with fishing line of up to about 200 feet long, which is sufficient in most practical uses of a video fishing pole system. Front side of the LED from which light is emitted has a cavity in a shape of a well, sized to receive an end of the fiber-optic line. The distal end of the fiber-optic line  9  is inserted trough a mechanical bracket  20  into the well of the LED  23 . The mechanical bracket nut  20 , O-ring  19  and a strain relief sleeve  18  for a collet or chuck assembly  21  to accomplish a reliable grip of the fiber  9  near the distal end. If a part of the fiber-optic line  9  is damaged, the distal end can be removed from the chuck assembly  21 , and a fresh distal end made by cutting the fiber-optic line with a sharp blade can be re-inserted through the strain relief sleeve and into the well of the LED  22 , and re-secured by tightening the bracket nut. 
     The O-ring  19  assures water tight seal at the fiber optic line entrance. The LED holder  57  can be part of the housing or bonded to it. The LED  22  also can be bonded to the holder  57 , thus providing an additional sealed barrier against water leakage. Likewise, the ring nut  28 , which holds the round window  32 , has an O-ring  29 , which assures a water tight seal at the front end of the housing  17 . Two clips  31  attached to the ring nut  28  are used to fasten the ends of a short piece of regular fishing line  13 , which support the leader  14 . A swivel  15  is attached to or rides near the middle of the support line  13 . The end of the leader  14  opposite the fishing hook  16  is tied to the swivel  15 . Preferably, the leader support line  13  has a tensile strength that is lower than the tensile strength of the optical fishing line  9 . Also, the grip of the optical fiber  9  provided by the bracketing contraption  20  is configured to be definitely stronger than the leader support line  13 , so that in a case the pulling force on the fishing hook  16  is overwhelmingly strong, the line  13  breaks, acting as a fuse. This provides an assurance that the submersible camera  11  remains attached to the fiber optic line  9 , to prevent loss of the camera  11  into the watery depths below. 
     The  FIG. 3  shows the pair of LED  70  and  71  mounted inside the submersible camera housing  11  against the window  32  near the viewing lens  30 . These LED produce light beam β either of near infrared or visible spectrum. This feature can be very useful for underwater observation at a substantial depth, at night or under the ice. 
     The  FIG. 4  and  FIG. 5  show how the proximate end of the fiber optic line  9  is wrapped around the spool  35 . The spool  35  is a part of the reel assembly  38 . The core of the spool has a shaft  34  that has a channel  41  going through the center of the shaft  34 , starting from one end of the shaft, then turning away from the axis at an elbow  62  (typically at an angle of about 45°, towards the cylindrical surface of the spool. The proximal end  33  of the fiber-optic line  9  first passes through the opening  36  in the spool drum  60 , and is secured to the outer surface of the drum  60  of the spool, such as with a bracket  37 . Then the fiber-optic line  9  goes through into the elbow  62  of the channel  41 , and exits channel  41  from the end of the shaft  34 . An optical receiver, shown as photo detector  40 , is housed in an extension of the reel  38  near the end of shaft  34 . The proximal end  41  of fiber-optic line  9  is inserted into a corresponding well of the photo detector  40 . 
       FIG. 6  shows another embodiment of a reel  38 . In this embodiment the spool has no metal shaft and is made of two identical plastic or metal cylindrical halves  48  and  49 . The halves are joined with screws or other fasteners protruding through mating channels  44 . Alternatively, they can be bonded ultrasonically or with glue or solvent. The plastic shaft extensions on each side are inserted in the bearings  42 . There are a round channels  41   a  and  41   b  made on the axis of the each half of the spool, respectively. On one side channel  41   a  is used as a conduit for the proximal end  33  of fiber-optic line  9 , directing it into the well of photo detector  40 . The ends  45   a  and  45   b  of the plastic shaft extensions are split into segments to serve as fingers of collet-type chucks. The ring  47  constricts these end  45   a  segments, thus clamping the end  33  of the fiber optic line  9  and secures its position in relation to the photo detector  40 . On the other side, the handle  7  sits on the segments  45 . The screw  46  inserted in the channel  41   b  expands the end  45   b  segments of the shaft extension, thus securing the handle and enable it to pass rotating torque to the spool. The fiber optic line  9  penetrates the cylindrical surface of the drum  60  of the spool via the arc shaped groove  43  created on the confronting surfaces of the abutted spool halves  48  and  49 . 
     Thus, the electrical video signal produced by the video device  26  and converted into the sequence of optical signals by the transmitter  23  with the LED  22 , travels via the fiber optic line  9  and reaches the photo detector  40 . The photo detector  40  converts the optical signal from the light form back into an electronic signal, which undergoes pre-processing by the receiver  39 . Almost all or a portion of the length of the fiber optic line  9  is coiled around the spool  35 . Typically, there is a small gap between the proximal end  41  of the fiber  9  and the receiving surface of the photo detector  40 . This thin gap, left empty or filled with a clear silicon gel for better optical coupling, allows reception of the image even when the spool  35  is revolving. The video signal processed by the receiver  39  travels to the input of the portable video monitor  2 , as shown on the  FIG. 7 . A suitable monitor  4  uses an LCD-type display panel equipped with a glare reflective or diffusing filter. Such monitor consumes little power and provides a good quality full color video image. When used in a bright sun light, a portable hood  5  helps to shade the screen from direct sun light for better contrast. In the next few years an organic LED (OLED) type portable displays are expected to become available. The OLED displays will offer even brighter image and improved contrast and power efficiency. The signal traveling through the fiber optic line is an analog video signal in a form of light energy amplitude-modulated by the TV signal produced by the video device  26  of the camera  11 . The receiver  39  produces an NTSC standard signal compatible with all kinds of video products including the recorders. Thus, as shown on  FIG. 7 , the video fishing rod system can have a standard RCA connector  56  with the video signal available for connecting to an outside recorder.  FIG. 7  presents the block diagram of the electronic and optical hardware of the invention. The battery power source  50 , video device  26 , LED driver  23  and LED  22  belong to the submersible camera unit  11 . A single AA alkaline cell was able to provide 10 hours of uninterrupted operation between battery changes, using a CMOS color camera, and a simple current amplifier with an LED  22  functioning as a load. A preferred LED for use with plastic fiber operates at about 650 nm. The red wavelength is recommended for minimum attenuation in plastic fibers. However, a near infrared LED working in the spectral band from 700 to 800 nm also can deliver good performance. A video fishing rod system using these wavelengths can easily operate with 100 to 200 feet long optical fishing lines. The optical fiber fishing line  9 , shown on the  FIG. 7 , optically connects the LED  22  with the receiving photo detector  40 , which is located inside the fishing reel  38  ( FIG. 6 ). The signal amplifier and conditioner  51  provide a standard NTSC signal to the LCD color monitor  4  and the auxiliary connector  56 . The connector  56  can be used to hook up external devices such as larger size monitor or video recorder. 
     The  FIG. 8  illustrates the way the submerged camera  11  looks when disposed in a horizontal direction with the help of string  54 . An eyelet  53  is attached to the side of the submersible camera housing  11  approximately at the level of its determined center of gravity. The clamp  55  securely grips the optical fiber line  9  at the point, which is a few body lengths off of the top of the camera housing  17 . The string  54  connects the eyelet  53  with the clamp  55 . The length of the string  54  is short enough to force the fiber line  9  to make a loop as shown on the  FIG. 8 , thus placing the camera in to a horizontal orientation. The strain relief sleeve  18  shown on the  FIG. 2  and  FIG. 8  prevents the fiber optic line  9  from excessively sharp bends at its attachment with the camera housing  17 . Alternatively, two eyelets  53   a  and  53   b  positioned on the side of the housing equidistantly from the center of gravity can be used. The string  54   a  is attached to them on both ends. The middle of the string is attached to the clamp  55 . This arrangement secures the underwater camera  11  in horizontal position. 
       FIG. 9  shows how the string  54 , when made long enough, can simply provide an additional back up security for prevention of camera loss. 
       FIG. 10  shows use of the submersible camera without a leader and a hook, simply for general observation. 
       FIG. 11  shows the leader  14  with the hook  16  is threaded through the swivel or a loop  15  that is attached to the center of the string  13  under the camera. The top end of the leader goes around the camera  11  and is connected to the clamp or a collet grip  55  positioned on the fiber optic line above the camera  11 . In this situation the point of mechanical connection of the main fiber optic line  9  to the camera housing  17  does not experience the pooling force applied to the fishing hook  16 . The loop or swivel  15  through which the leader line is threaded keeps the hook in the field of view α of the camera. 
     A working prototype has been built and successfully tested in both fresh and salt waters of Florida.