Abstract:
A video telecommunications device and a camera unit for a video telecommunications device. A camera is mounted on the telecommunications device by a motor capable of rotating the camera on the telecommunications device. A position sensor senses the rotational position of the camera on the telecommunications device, and a position control input device enables provision of a control signal indicating a desired rotational position for the camera on the telecommunications device. A controller that is responsive to the control signal and the sensed position of the camera causes the motor to rotate the camera so as to position the camera in the desired rotational position on the telecommunications device, providing the desired video picture. A telecommunications coupler couples the camera unit to the telecommunications device, enabling the telecommunications device to communicate the image sensed by the camera lens to a receiving telecommunications device.

Description:
FIELD OF THE INVENTION 
     The present invention pertains to a camera unit for a telecommunications device and to a video telecommunications device. 
     BACKGROUND OF THE INVENTION 
     Video telecommunications devices are available with fixedly mounted cameras which must be manually positioned so that the camera lens senses a desired image. While such video telecommunications devices are well suited for use in situations in which the object of which the image is desired remains within a relatively small area, for example a witness testifying in a video-telephonic deposition, in many situations in which it is desired to have a video telecommunication capability the object of which the video image is desired might change. For example, it might be desired to provide a video telecommunication capability of a technical conference at which several people are to speak from different locations within the conference room, or at which questions are to be taken from audience members. Such a situation requires rotation of the camera to position the camera lens so as to sense the desired image. With a fixed camera, such usage is very difficult, if not wholly impractical. 
     Many telephone conversations are accomplished using wireless telephones. Such wireless phones are considerably smaller than desk phones. To provide a video capability with a wireless phone requires a small, low power, lightweight camera. The ability to rapidly and smoothly rotate such a camera so as to readily obtain the intended image is also desirable. 
     SUMMARY OF THE INVENTION 
     The present invention is a video telecommunications device and a camera unit for a video telecommunications device. A camera is mounted on the telecommunications device by a motor capable of rotating the camera on the telecommunications device. A position sensor senses the rotational position of the camera on the telecommunications device, and a control device enables provision of a control signal indicating a desired rotational position for the camera on the telecommunications device. A controller that is responsive to the control signal and the sensed position of the camera causes the motor to rotate the camera so as to position the camera in the desired rotational position on the telecommunications device. Accordingly, the desired video picture can be obtained. A telecommunications coupler couples the camera unit to the telecommunications device, enabling the telecommunications device to communicate the image sensed by the camera lens to a receiving telecommunications device. Thus, improved video conferencing is possible. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other aspects and advantages of the present invention are more apparent from the following detailed description and claims, particularly when considered in conjunction with the accompanying drawings in which like parts bear like reference numerals. In the drawings: 
     FIG. 1 is a diagrammatic depiction of a video telecommunications device in accordance with a preferred embodiment of the present invention; 
     FIG. 2 is a block diagram of a first embodiment of a camera unit suitable for use in the video telecommunications device of FIG. 1 in accordance with the present invention; 
     FIG. 3 is a perspective view of a first embodiment of a camera, motor, and position sensor assembly suitable for use in the video telecommunications device of FIG. 2 in accordance with the present invention; 
     FIG. 4 is a perspective view of a second embodiment of a camera, motor, and position sensor assembly suitable for use in the video telecommunications device of FIG. 2 in accordance with the present invention; and 
     FIG. 5 is a block diagram of a second embodiment of a camera unit suitable for use in the video telecommunications device of FIG. 1 in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 is a diagrammatic depiction of a video telecommunications device  10  in accordance with a preferred embodiment of the present invention. Video telecommunications device  10  includes a telephone  12  and a video camera unit  14 . Telephone  12  permits communication over a telephone connection  13  to another telephone, as is well known. Telephone  12  might be a wireless phone such as a cell phone, or a landline phone such as a desk phone or a wall phone. Video camera unit  14  senses a video image that is transmitted over the telephone connection together with audio or data from telephone  12 , providing a video telecommunications capability. 
     FIG. 2 is a block diagram of a first embodiment of a camera unit  14  in accordance with the present invention. Camera unit  14  includes a video camera  16  having a lens  18  to sense an image. Camera  16 , which for example might be a CCD camera or a CMOS camera, is mounted on a motor  20  which, in turn, is mounted on the telecommunications device, such as telephone  12 . Motor  20  is coupled to motor controller  22 . Under the control of motor controller  22 , motor  20  is capable of rotating camera  16  about a shaft  23  on telephone  12 . A position sensor  24  senses the rotational position of camera  16  on telephone  12 . A system controller  26  is connected to camera  16 , motor controller  22 , and position sensor  24 . System controller  26  receives position signals from position sensor  24  and control signals from a position control input device  28 . In response to the control signals and the sensed camera position, system controller  26  instructs motor controller  22  to cause motor  20  to rotate camera  16  until the position signals from position sensor  24  indicate that the camera has rotated to the desired rotational position as indicated by the signals from position control input device  28 . 
     A telephone coupler  30  connects system controller  26  to telephone  12  to permit transmission of the visual images sensed by lens  18  and the sensor of camera  16  over the telephone connection to a receiving video telecommunications device at a remote location and receipt of visual images from that remote telecommunications device. A video display device  32 , such as a thin film transistor display device or a liquid crystal display device, is connected to system controller  26 . Display device  32  thus can display images sensed by a camera unit on the telecommunication device at the remote location. Additionally, display device  32  can display the image sensed by lens  18  and the sensor of camera  16  so as to assure that the image is properly positioned and focused. 
     FIG. 3 is a perspective view of a first embodiment of a camera, motor, and position sensor assembly suitable for use in camera unit  14  in accordance with the present invention. Camera  16  has a cylindrical housing with a lens  18  in the cylindrical side thereof. In the embodiment of FIG. 3, motor  20  is a ceramic motor having a shaft  23  on which the cylindrical housing of camera  16  is mounted, permitting the camera to rotate about that shaft, and so changing the rotational position of lens  18 . By way of example, ceramic motor  20  might be a motor of the type depicted in U.S. Pat. No. 5,714,833, issued Feb. 3, 1998, the disclosure of which is incorporated herein by reference. Ceramic motor  20  includes a rectangular piezoelectric ceramic  40  and a disk  42 . From one end of piezoelectric ceramic  40  a spacer or fingertip (not shown) extends radially with respect to disk  42  to contact the circumferential surface of disk  42 . The housing of camera  16  is mounted by shaft  23  on disk  42 . 
     Piezoelectric ceramic  40  has a planar surface with a set of four electrodes  46  mounted thereon, on the upper right, upper left, lower right, and lower left quadrants of the planar surface. When a high frequency ac voltage, for example a voltage of 40 kHz, is applied across a first diagonally opposite pair of the electrodes  46 , the piezoelectric effect results in an oscillatory mode of longitudinal extending and transverse bending of piezoelectric ceramic  40 . This causes the fingertip to move in a small elliptical path, causing the fingertip to repeatedly push and release disk  42 , rotating the disk, and so rotating camera  16 . Preferably, disk  42  has one or more radial stripes  47  on its surface. Position sensor  24  can then be a set of optical sensors, for example three optical sensors, mounted adjacent that surface of disk  42  to sense the stripes  47  as they rotate to positions beneath the sensors. If the ac voltage is applied across the other pair of diagonally opposite electrodes on piezoelectric ceramic  40 , the fingertip moves in a small elliptical path in the other direction, causing the fingertip to rotate disk  42 , and thus camera  16 , in the opposite direction. Accordingly, camera  16  can be caused to rotate to a desired position. 
     To rotate camera  16 , position control input device  28 , which might be a simple pushbutton, is actuated, applying a brief control signal to system controller  26 . System controller  26 , in turn applies a signal to motor controller  22 , causing the motor controller to actuate motor  20 , rotating disk  42  and camera  16  about shaft  23 . 
     When it is desired to rotate camera  16  a small rotational amount, position control input device  28  is actuated for a brief time, less than a predetermined time t. In response system controller  26  applies a signal to motor controller  22  causing the motor controller to actuate motor  20  to rotate camera  16  by a small amount. Repeated actuations of position control input device  28  cause camera  16  to rotate in small steps to a desired position, with the number of actuations of motor  20  determining the amount of rotation of disk  42  and camera  16 . Position sensor  24  can apply count signals to a memory within position controller  26  to keep a record of the rotational position of lens  18 . 
     When it is desired to rotate camera  16  to a predetermined position, position control input device  28  is actuated for a longer time, greater than predetermined time t. In response system controller  26  applies a signal to motor controller  22  causing the motor controller to actuate motor  20  to rotate camera  16  to that position, as determined by position sensor  24 . 
     FIG. 4 is a perspective view of a second embodiment of a camera and motor, suitable for use in the present invention, the sensor assembly having been omitted from the figure for clarity. First and second ceramic motors  20   a ,  20   b  are mounted on diametrically opposite sides of disk  42 . Fingertip  48   a  of ceramic motor  20   a  extends radially with respect to disk  42 , substantially parallel with shaft  23  of camera  16 , to contact the planar surface of disk  42  adjacent the circumferential edge thereof. Shaft  23  rotatably mounts camera  16  and disk  42  on housing  50  of the motor assembly in FIG.  4 . Ceramic motor  20   a  includes a spring  52   a  which biases fingertip  48   a  into contact with the planar surface of disk  42 . Ceramic motor  20   b  is similarly constructed to position its fingertip (not shown) against the planar surface of disk  42  at a point diametrically opposite the point of contact of fingertip  46   a.    
     An ac voltage applied across a first diagonally opposite pair of the electrodes of each of the ceramic motors  20   a  and  20   b , causes the fingertips of the motors to move in small elliptical paths, causing repeated slight rotation of disk  42  in a first direction, and so rotating camera  16  in this direction. If an ac voltage is applied across the other diagonally opposite pair of the electrodes of ceramic motors  20   a ,  20   b , the fingertips move in small elliptical paths in the opposite direction, rotating disk  42  and camera  16  in the opposite direction. Thus, camera  16  can be rotated to a desired position. 
     In the embodiment of FIG. 2, position control input device  28  might cause system controller  26  to always apply a voltage across the same pair of electrodes of motor  20 , thus always rotating disk  42  and camera  16  in the same direction. Alternatively, controller  20  might be programmed so that if a predetermined interval of time passes between consecutive input pulses from position control input device  28 , the controller changes the pair of electrodes to which the voltage is applied, causing rotation in the opposite direction. Likewise, a direction control input device might be provided, if desired, or other direction control techniques might be utilized. 
     FIG. 5 illustrates an alternative embodiment in which separate front and back position control input devices  28   a ,  28   b  are provided to permit selection of the direction of rotation of camera  16 , to bring the lens  18 , either toward the front or toward the back of the camera. FIG. 5 also illustrates that motor controller  22  and system controller  26  can be consolidated into a single controller  25 . Controller  25 , or controllers  22  and  26 , can be a properly programmed processor, for example. 
     Ceramic motor  20  is small and light weight and has low power requirements, making such a motor well suited for use in a video telecommunications device in accordance with the present invention, particularly when the telecommunications device is a wireless phone. If a larger telecommunications device, such as a desk phone, is to be used, then a ceramic motor is still advantageous, but alternatively a stepper motor or a solenoid might be used in accordance with the present invention, particularly if a power supply is available, rather than a battery. 
     The present invention thus provides a video telecommunication device capable of rapidly rotating a video camera to a desired position so as to provide a desired video image. Although the invention has been described with reference to preferred embodiments, various alterations, rearrangements, and substitutions might be made, and still the result would be within the scope of the invention.