Patent Publication Number: US-2007109269-A1

Title: Input system with light source shared by multiple input detecting optical sensors

Description:
BACKGROUND  
      Many different types of input devices have been developed for inputting commands into a machine. For example, hand-manipulated input devices, such computer mice, joysticks, trackballs, touchpads, and keyboards, commonly are used to input instructions into a computer by manipulating the input device. Such input devices allow a user to control movement of a virtual pointer, such as a cursor, across a computer screen, select or move an icon or other virtual object displayed on the computer screen, and open and close menu items corresponding to different input commands. Input devices commonly are used in both desktop computer systems and portable computing systems.  
      Input devices typically include a mechanism for converting a user input into user interface control signals, such as cursor position data and scrolling position and distance data. Some types of input devices use electromechanical transducers to convert user manipulations of the input device into electrical signals that can be converted into user interface control signals. Other types of input devices use optoelectronic transducers to convert user manipulations of the input device into user interface control signals. Optoelectronic transducer based input devices tend to have improved resistance to degradation by contamination and wear relative to electromechanical transducer based input devices. Optoelectronic transducers, however, tend to require significantly more power than electromechanical transducers, which a significant factor in the design of wireless input devices that communicate with host computer systems over a wireless connection and draw power from a portable power source, such as a battery.  
      Although power management techniques typically are used to increase the efficiency with which power is used in optoelectronic transducer based input devices, additional ways to reduce the power requirements of optoelectronic transducer based input devices are needed.  
     SUMMARY  
      In one aspect, the invention features an input system that includes a light source, a first optical sensor, a second optical sensor, and a processing system. The light source illuminates a first scene that changes in response to a first user input and a second scene that changes in response to a second user input. The first optical sensor has a first field of view of the first scene and produces first electrical signals in response to light from the light source in the first field of view. The second optical sensor has a second field of view of the second scene and produces second electrical signals in response to light from the light source in the second field of view. The processing system respectively produces first and second user interface control signals from the first and second electrical signals.  
      In another aspect, the invention features an input method in accordance with which light is produced from a source illuminating a first scene that changes in response to a first user input and a second scene that changes in response to a second user input. First electrical signals are produced in response to the light illuminating the first scene in a first field of view. Second electrical signals are produced in response to the light illuminating the second scene in a second field of view. First and second user interface control signals are respectively produced from the first and second electrical signals.  
      Other features and advantages of the invention will become apparent from the following description, including the drawings and the claims. 
    
    
     DESCRIPTION OF DRAWINGS  
       FIG. 1  is a block diagram of an embodiment of an input device.  
       FIG. 2  is a flow diagram of an embodiment of a method implemented by the input device shown in  FIG. 1 .  
       FIG. 3  is a block diagram of an embodiment of the input device shown in  FIG. 1 .  
       FIG. 4  is a block diagram of an embodiment of the input device shown in  FIG. 1 .  
       FIG. 5  is a perspective view of a housing containing an embodiment of the input device shown in  FIG. 4 .  
       FIG. 6  is a perspective view of the input device embodiment shown in  FIG. 5  with the top portion of the housing removed.  
       FIG. 7  is a schematic view of an encoder and an embodiment of a first optical sensor in an embodiment of the input device shown in  FIG. 4 .  
       FIG. 8  is a block diagram of an embodiment of the input device shown in  FIG. 1 . 
    
    
     DETAILED DESCRIPTION  
      In the following description, like reference numbers are used to identify like elements. Furthermore, the drawings are intended to illustrate major features of exemplary embodiments in a diagrammatic manner. The drawings are not intended to depict every feature of actual embodiments nor relative dimensions of the depicted elements, and are not drawn to scale.  
      The embodiments that are described in detail below reduce the power requirements of input devices that use optoelectronic transducers to convert user manipulations into user interface control signals by sharing the light generated by a light source among multiple input detecting optical sensors. In addition to reducing power requirements, these embodiments reduce costs relative to input devices that have a respective light source for each of multiple input detecting optical sensors.  
       FIG. 1  shows an embodiment of an input device  10  that includes a light source  12 , a first optical sensor  14 , a second optical sensor  16 , and a processing system  18 . The input device  10  may be incorporated into any type of input device form factor, including a computer mouse, a joystick, a trackball, and a steering wheel controller.  
      The light source  12  may be any type of light source that is capable generating light that can be sensed by the first and second optical sensors  14 ,  16 . In some embodiments, the light source  12  is implemented by a light emitting diode that is capable of producing light within a specified wavelength range that is detectable by the first and second optical sensors  14 ,  16 . The specified wavelength range typically is within the visible light spectrum or within the infrared light spectrum.  
      The first and second optical sensors  14 ,  16  may be any type of optical sensors that are capable of optically sensing user manipulations of a component of the input device  10  (e.g., a touch pad, a trackball, or a joystick) or manipulations of the input device  10  itself (e.g., movement of the input device  10  across a surface or through the air). The first and second optical sensors  14 ,  16  may include one or more of any type of photodetector device, including a single photosensor, a one-dimensional optical detector (e.g., a linear array of photodiodes), and a two-dimensional optical detector (e.g., a CCD or CMOS image sensor device). In some embodiments, the first and second optical sensors  14 ,  16  correspond to different respective parts of a single optical device. For example, in some of these embodiments, the first and second optical sensors  14 ,  16  correspond to non-overlapping regions of an array of optical detectors.  
      The processing system  16  may be implemented by one or more discrete modules that are not limited to any particular hardware or software configuration. The one or more modules may be implemented in any computing or processing environment, including in digital electronic circuitry (e.g., an application-specific integrated circuit, such as a digital signal processor (DSP)) or in computer hardware, firmware, device driver, or software.  
       FIG. 2  shows a flow diagram of an embodiment of a method that is implemented by the input device  10 . In accordance with this method, the light source  12  illuminates a first scene  20  that changes in response to a first user input  22  and a second scene  24  that changes in response to a second user input  26  ( FIG. 2 , block  28 ). In general, the first and second scenes  20 ,  24  are changed independently of one another (e.g., the first user input  22  changes the first scene  20  without changing the second scene  24 , and the second user input  26  changes the second scene  24  without changing the first scene  20 ). The first and second user inputs  22 ,  26  may be the same type of user input (for example: manipulation of a movable member, such as a rotatable wheel, a slidable slider, a rotatable ball, a movable stylus, or a movable stick first; and manipulation of the entire input device  10 ) or they may be different types of user input (e.g., manipulation of a movable member and manipulation of the entire input device  10  across a surface).  
      The first optical sensor  14  produces first electrical signals  30  in response to the light illuminating the first scene  20  in a first field of view  32  ( FIG. 2 , block  34 ). The first field of view  32  corresponds to the area of the first scene  20  that is visible to the active light-sensing elements of the first optical sensor  14 . The second optical sensor  16  produces second electrical signals  36  in response to the light illuminating the second scene  24  in a second field of view  38  ( FIG. 2 , block  40 ). The second field of view  38  corresponds to the area of the second scene  24  that is visible to the active light-sensing elements of the second optical sensor  16 . The processes of blocks  34  and  40  may be performed sequentially or concurrently.  
      The processing system  18  respectively produces first and second user interface control signals  42  from the first and second electrical signals  30 ,  36  ( FIG. 2 , block  44 ). Examples of the types of user interface control signals that may be produced by the processing system  18  include cursor position and movement data and scrolling position and distance data. In the embodiment shown in  FIG. 1 , the first and second user interface control signals  42  are transmitted to a computer  45  over a communication link  47  (e.g., a serial communication link, such as an RS-232 serial port, a universal serial bus, or a PS/2 port). In operation, the computer  45  executes a driver in an operating system or an application program that processes the first and second user interface control signals to control the display and movement of a pointer  49  on a computer monitor  51 .  
       FIG. 3  shows a block diagram of an input device  50  that is an embodiment of the input device  10 . In the input device  50 , the first scene  20  is a surface of an encoder  52 , which is mechanically connected to a movable member  54 , and the second scene  24  is a surface  56  with respect to which the input device  50  may be moved by a user. The light source  12  illuminates the first and second scenes  20 ,  24  with light  58 ,  59 . The light source  12  may include one or more optical elements for guiding and shaping the light  58 ,  59  that illuminates the first and second scenes  20 ,  24 .  
      The movable member  52  may include a rotatable wheel, a slidable slider, a rotatable ball, a movable stylus, a movable stick, or a movable button (e.g., a right or left computer mouse button), depending on the target application for the input device  50 . The encoder  52  may be connected to the movable member  54  by a separate and distinct element, such as a rotatable shaft, or the encoder  52  may be attached to or formed on a surface of the movable member  54 .  
      The encoder  52  modulates light  60  from the light source  12  in the first field of view  32  with information that encodes movement of the movable member  54 . In general, the encoder  52  may be implemented by any type of device that is capable of modulating the light  60  with position encoding information. In some embodiments, the encoder  52  includes a coded pattern of light modulating regions, where the position of the coded pattern in the first field of view  32  changes with movement of the movable member  54 . In the embodiment shown in  FIG. 3 , the encoder  52  includes a coded pattern of regions having different light reflectivity. The regions of different reflectivity may correspond to reflective regions and non-reflective regions (e.g., absorptive regions or translucent regions).  
      In some implementations, the first optical sensor  14  produces an electrical signal  62  that tracks the intensity of the light  60  that is modulated by the encoder  52 . The electrical signal  62  includes peaks at the times when the reflective regions of the encoder  52  are in the first field of view  32  and valleys at the times when the non-reflective regions of the encoder  52  are in the first field of view  32 . The processing system  18  determines the position of the encoder  52  from the peaks and valleys in the electrical signal  62 .  
      In other implementations, the first optical sensor  14  includes two optical detectors each of which produces a respective electrical signal from the modulated light  60  reflecting from a different region in the first field of view  32 . In these implementations, the coded pattern of the encoder  52  and the respective fields of view of the optical detectors are configured so that the electrical signals produced by the optical detectors are in quadrature (i.e., out of phase, e.g., by 90°). The processing system  18  determines the position and direction of motion of the encoder  52  from the quadrature electrical signals using quadrature signal processing techniques and translates the determined motion into user interface control signals  42 .  
      In some embodiments, the second optical sensor  16  corresponds to an optical navigation sensor module that includes an imager  64  and a movement detector  66 . The imager  64  may be any form of imaging device that is capable of capturing one-dimensional or two-dimensional images of the surface  56 . The imager  64  includes at least one image sensor. Exemplary image sensors include one-dimensional and two-dimensional CMOS (Complimentary Metal-Oxide Semiconductor) image sensors and CCD (Charge-Coupled Device) image sensors. The imager  64  captures images at a rate (e.g., 1500 pictures or frames per second) that is fast enough so that sequential pictures of the surface  56  overlap. The imager  64  may include one or more optical elements that focus light  68  from the light source  12  that reflects from the surface  56  onto the one or more image sensors.  
      The movement detector  66  may be part of the processing system  18  or it may be part of the second optical sensor  16  as shown in  FIG. 3 . The movement detector  66  is not limited to any particular hardware or software configuration, but rather it may be implemented in any computing or processing environment, including in digital electronic circuitry or in computer hardware, firmware, or software. In one implementation, the movement detector  66  includes a digital signal processor (DSP). The movement detector  66  detects relative movement between the input device  50  and the surface  56  based on comparisons between images of the surface  56  that are captured by the imager  64 . In particular, the movement detector  66  identifies texture or other features in the images and tracks the motion of such features across multiple images. These features may be, for example, inherent to the surface  56 , relief patterns embossed on the surface  56 , or marking patterns printed on the surface  56 . The movement detector  66  identifies common features in sequential images and determines the direction and distance by which the identified common features are shifted or displaced.  
      In some implementations, the movement detector  66  correlates features identified in successive images to provide information relating to the position of the surface  56  relative to the imager  64 . In general, any type of correlation method may be used to track the positions of features across successive images. In some embodiments, a sum of squared differences correlation method is used to find the locations of identical features in successive images in order to determine the displacements of the features across the images. In some of these embodiments, the displacements are summed or integrated over a number of images. The resulting integration values may be scaled to compensate for any image scaling by the optics associated with the imager  64 . The movement detector  66  translates the displacement information into two-dimensional relative motion vectors (e.g., X and Y motion vectors) that describe the relative movement of the input device  50  across the surface  56 . The processing system  18  produces the user interface control signals  42  from the two-dimensional motion vectors.  
      Additional details relating to the image processing and correlating methods that are performed by the movement detector  66  can be found in U.S. Pat. Nos. 5,578,813, 5,644,139, 5,703,353, 5,729,008, 5,769,384, 5,825,044, 5,900,625, 6,005,681, 6,037,643, 6,049,338, 6,249,360, 6,259,826, 6,233,368, and 6,927,758. In some embodiments, the imager  64  and the movement detector  66  may be implemented by an optical mouse navigation sensor module (e.g., the ADNS-2051 optical mouse navigation sensor available from Agilent Technologies, Inc. of Palo Alto, Calif., U.S.A.).  
       FIG. 4  shows a block diagram of an input device  70  that is an embodiment of the input device  10 . The input device  70  is similar to the input device  50  that is shown in  FIG. 3 , except that the first optical sensor  14  is located between the encoder  52  and the movable member  54  and the input device  70  includes optical elements (e.g., one or more refractive optical elements, diffractive optical elements, light pipes, and optical waveguides) for guiding and shaping the light from the light source  12  that illuminates the first and second scenes and an optical element for focusing the light reflecting from the surface  56  onto the active regions of the imager  64 .  
      In this embodiment, the encoder  52  is connected to the movable member  54  by a rotatable shaft  71 . The encoder  52  includes a coded pattern of opaque and translucent regions. The first optical sensor  14  has a field of view of the modulated light from the light source  12  that is transmitted through the translucent regions of the encoder  52 .  
      In the input device  70 , the light source  12  is implemented by a light emitting diode  72  and an optical element  74  that collimates the light  75  that is produced by the light emitting diode  72 . A beam splitter  76  (e.g., a plate beam splitter, a cube beam splitter, a pellicle beam splitter, or a perforated beam splitter) divides the collimated light into a first beam  78  and a second beam  80 . The first beam  78  is directed to an optical element  82  (e.g., a lens), which focuses the first beam  78  onto the encoded light-modulating pattern of the encoder  52 . The second beam  80  is directed to an optical element  84  (e.g., a mirror) that directs the second beam  80  to the surface  56  through an optical port  86  that is formed in an exterior wall  88  of the input device  70 . A portion of the second beam  80  that reflects from the surface  56  is focused by an optical element  90  onto the active areas of the imager  64 .  
       FIG. 5  shows a perspective view of an embodiment of a housing  100  that contains an embodiment of the input device  70 . The housing  100  includes a base  102  and a top portion  104 . The housing  100  also includes a right input button  106 , a left input button  108 , and an opening  110  through which the movable member  54  extends. In this embodiment, the movable member  54  is implemented by a rotatable wheel  112  (e.g., a Z-axis control wheel or a Z-wheel).  
       FIG. 6  is a perspective view of the input device embodiment shown in  FIG. 5  with the top portion of the housing  100  removed. For clarity of presentation, the optical elements  74 ,  76 ,  82 , and  84  are not shown in  FIG. 6 . The movable member  54  and the encoder  52  are mounted on the shared rotatable shaft  71 . The encoder  52  is implemented by a prior art code disk that includes a set of equally spaced teeth  114  and a set of slots  116  that are formed between adjacent ones of the teeth. In other embodiments, the encoder  52  may be implemented by a translucent disk that includes a radially spaced pattern of grating lines. Right and left switches  115 ,  117  are used to detect when a user has activated the right and left input buttons  106 ,  108 , respectively.  
       FIG. 7  shows a schematic view of the prior art code disk implementation of the encoder  52  and a prior art implementation of the first optical sensor  14  that includes a first optical detector  118  and a second optical detector  120 . The first and second optical detectors  118 ,  120  typically are implemented by photodiodes. In operation, the code disk rotates when the wheel  112  is rotated by a user. The light  78  from the light source  12  is blocked by the teeth  114  of the code disk as they rotate into position in front of the respective fields of view of the first and second optical detectors  118 ,  120 . The first and second optical detectors  118 ,  120  are configured with respect to the pattern of teeth  114  and slots  116  of the code disk so that they produce output electrical signals  122 ,  124  in quadrature. Thus, when the code disk is rotated at a constant rate, the first and second optical detectors  118 ,  120  respectively produce electrical signals that vary sinusoidally and are 90° out of phase. The output electrical signals  122 ,  124  are passed to first and second Schmitt triggers  126 ,  128 , which reduce noise in the output electrical signals  122 ,  124 . The processing system  18  processes the resulting first and s second quadrature signals  130 ,  132  to determine the motion of the encoder  52 .  
       FIG. 8  is a block diagram of an input device  140  that is an embodiment of the input device  10 . In addition to the first and second optical sensors  14 ,  16  and the processing system  18 , the input device  140  includes a wireless transmitter  142 , a power controller  144 , a rechargeable power supply  146 , and a docking interface  150 . The processing system  18  delivers the user interface control signals  42  to the wireless transmitter  142  in a format that is suitable for reception by a host computer system. The wireless transmitter  142  may be implemented by any one of a wide variety of different wireless transmitters, including an RF transmitter and an IR transmitter. The rechargeable power supply  146  may be any type of battery or other electrical power store that can be recharged by an external power source through the docking interface  150 . The power controller  144  controls the supplying of power from the rechargeable power supply  146 . In some embodiments, the power controller  144  is part of the processing system  18  instead of a separate component as shown in  FIG. 8 .  
      In general, the power controller  144  may implement any one of a wide variety of different power management algorithms. In some embodiments, when the input device  140  has not received any input from a user for a specified period the power controller  144  changes the input device  140  from an active power mode (or full power mode) to a standby or idle mode, during which the light source  12  is turned off. The power controller  144  transmits to the processing system  18  a power mode status signal  152 , which has a variable value that indicates the current power mode of the input device  140 . In these embodiments, the processing system  18  selectively processes the electrical signals produced by the first and second optical sensors  14 ,  16  into the user interface control signals  42  in response to the value of the power mode status signal  152 . In particular, when the input device  140  is in the active power mode, the processing system  18  processes the electrical signals from the first and second optical sensors  14 ,  16  as described above. When the input device  140  is in the idle power mode, on the other hand, the processing system  18  discontinues processing the electrical signals from the first and second optical sensors  14 ,  16 . In this way, erroneous user interface control signals that otherwise might be produced due to the lack of sufficient lighting by the light source  12  may be avoided.  
      Other embodiments are within the scope of the claims.