Patent Publication Number: US-8994694-B2

Title: Optical interference based user input device

Description:
FIELD OF THE DISCLOSURE 
     The present disclosure generally relates to user interfaces for electronic devices and more particularly to user input interfaces. 
     BACKGROUND 
     Portable or handheld electronic devices including cellular phones and the like comprise user interface input devices that allow a user to interact with items presented on a display. Examples of user interface input devices include arrow keys, trackballs, trackpads, and more recently, optical navigation modules (ONMs) that detect finger movement. ONMs generally sense a gesture performed upon the module by a user&#39;s finger. In conventional ONMs, light is directed to a light transmitting surface upon which an object, such as one or more fingers, are moved. The finger reflects light to a sensor beneath the surface, which transmits information to a processor corresponding to light reflected from the moving finger. The processor interprets the movement of patterns of transmitted data in order to determine the corresponding movement of the finger. In this manner, gestures may be communicated from the user to a processor of the computing device. 
     However, the performance and effectiveness of conventional ONMs can become hindered as a result of their reliance on specular reflection since environmental factors can affect a conventional ONM&#39;s ability to properly detect light reflections. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying figures where like reference numerals refer to identical or functionally similar elements throughout the separate views, and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present disclosure, in which: 
         FIG. 1  illustrates a portable electronic device with an optical interference based user input device in accordance with one example; 
         FIG. 2  illustrates a conventional optical sensor for a conventional user input device; 
         FIG. 3  is a top-side perspective view of the optical interference based user input device of  FIG. 1 , in accordance with one example; 
         FIGS. 4-5  are cross-sectional views of the optical interference based user input device of  FIG. 3 , in accordance with one example; 
         FIG. 6  illustrates an image captured by the image sensor of the optical interference based user input device of  FIG. 2 , in accordance with one example; 
         FIG. 7  is a cross-sectional view of the optical interference based user input device of  FIG. 3  showing a user interacting with a touch surface of the device, in accordance with one example; 
         FIGS. 8-11  illustrate various images comprising an interference pattern(s) captured by the image sensor of the optical interference based user input device of  FIG. 2  as a result of a user interacting with the touch surface of the device, in accordance with one example; 
         FIG. 12  illustrates an optical interference based user input device management process, in accordance with one example; 
         FIG. 13  illustrates electrical connections between sensors optical interference based user input device of  FIG. 3  and a controller/processor, in accordance with one example; 
         FIG. 14  is a block diagram of an electronic device and associated components in which the systems and methods disclosed herein may be implemented; 
         FIG. 15  illustrates an example of a second set of patterns being displaced with respect to a first set of patterns; 
         FIGS. 16-19  illustrate examples of interference patterns with in various configurations; and 
         FIGS. 20-23  is a set of interference patterns being created as a result of the user placing his/her finger on the touch surface. 
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments are disclosed herein; however, it is to be understood that the disclosed embodiments are merely examples and that the systems and methods described below can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the disclosed subject matter in virtually any appropriately detailed structure and function. Further, the terms and phrases used herein are not intended to be limiting, but rather, to provide an understandable description. 
     The terms “a” or “an”, as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms “including” and “having,” as used herein, are defined as comprising (i.e., open language). The term “coupled,” as used herein, is defined as “connected,” although not necessarily directly, and not necessarily mechanically. 
     Operating Environment 
       FIG. 1  illustrates a portable electronic device  100  with an optical interference based user input device  102  in accordance with one example. The portable electronic device  100  in this example is a portable smartphone that supports cellular voice communications and also data communications with a central network. In one example, the electronic device  100  performs data communications with a wireless network to support accessing and exchanging data over the Internet. Data received by the electronic device is displayed on a display  104  (also referred to herein as a “user interface display  104 ”), which is able to be an alpha-numeric only display or a graphical display, and may or may not have touchscreen capabilities. In one example, the display  104  presents a graphical user interface for a user to access functions and to receive information. 
     The electronic device  100  is housed within a device case  106 . The display  104  is presented on one side of the device case  106 . An alpha-numeric keyboard  108  is also physically presented on the same side of the device case  106  as the display  104 . In various examples, the alpha-numeric keyboard  108  is able to be a QWERTY keyboard, a numeric telephone keypad, a virtual or “soft” keyboard implemented by key images rendered on a touchscreen display, or any suitable user input device. 
     The electronic device  100  further includes a number of function keys. The illustrated electronic device  100  has a first function key  110 , a second function key  112 , a third function key  114 , and a fourth function key  116 . These function keys are able to be associated with a dedicated function, such as presenting an interface to initiate a voice call whenever pressed, or the function key is able to be associated with different functions based upon a current operating mode of the electronic device  100 . 
     The electronic device  100  further has an optical interference based user input device  102  (also referred herein to as “input device  102 ”). The design and operation of the input device  102  is discussed in further detail below. The input device  102  of one example is a finger/object movement sensing device on which a user performs a gesture and/or presses with a finger. The input device  102  identifies/tracks the gesture and/or determines a location of a user&#39;s finger on the input device  102 . 
     As used herein, the term press (and its derivatives) indicates any touching of a touch surface  304  ( FIG. 3 ) of the input device  102  with an amount of pressure in a direction substantially normal to the touch surface  232  and sufficient to differentiate a gesture of moving an object in contact with and across the touch surface  304  in a given substantially horizontal plane. The term press is contrasted with a gesture of pushing, for example in a direction generally or substantially not parallel to a surface of touch surface  304 . Accordingly, a press does not require a corresponding movement of the touch surface, but merely the detection by input device  102  of such general or substantially non-parallel pressure that may be differentiated or distinguished from a generally coplanar or parallel movement across a surface of the touch surface  304 . 
     In one example, with respect to finger movement navigation, the input device  102  detects a sliding, dragging, pushing, or pulling movement of a user&#39;s finger or stylus (or similar object) across the touch surface  304 . The input device  102  distinguishes a gestural movement from a pressing action based on the amount of pressure applied during the gesture and/or the specific movement involved during the gesture. Based upon a starting position and ending position of the gestural movement (and optionally any intermediate positions) a user input direction is determined. In one operating mode of the electronic device  100 , processing determines a direction to move a user interface element based upon the attributes/characteristics of the detected gestural movement, and optionally determines a magnitude, such as distance to move the element or speed with which to move the element, based upon a velocity, acceleration, and/or deceleration of the user&#39;s finger or stylus during the gestural movement. 
     In another example, the input device  102  can accept movement in various directions by the user&#39;s finger or a stylus. For example, the user is able to push or pull along the touch surface  304  (or sensor cover  302  ( FIG. 3 )) in multiple directions along the X/Y plane. The user is also able to tilt the input touch surface  304  in various directions along its center axis. The degree of tilt, in one example, can be varied by the user. In either example, the user is also able to press the touch surface  304  as the input device is being moved/tilted, hold the touch surface  304  at a tilted or a pushed/pulled position, and vary the degree of pressure. The touch surface  304  determines the direction (and optionally degree) of movement or tilt as well as a magnitude of pressure exerted by the user onto the touch surface  304 . Based upon the direction (and optionally degree) of movement and amount of pressure that has been determined, a user input direction and magnitude is determined. In one operating mode of the electronic device  100 , processing determines a direction to move a user interface element based upon the detected movement, and determines a magnitude, such as distance to move the element or speed with which to move the element, based upon the pressure (and optionally the degree of movement as well). 
     Conventional Optical Sensors 
       FIG. 2  illustrates a conventional a prior art optical sensor  200  utilized by conventional user input devices. The prior art optical sensor  200  includes a light emitter  202  and a light sensor  204 . A touch surface  206  is positioned proximate to the emitter  202  and the sensor  204 , and defines a thickness between an upper surface  208  and a lower surface  210 . In a typical use of the sensor  200 , a fingertip or other object  212  controlled by a user moves upon the touch surface  206  and causes a reflection of light emitted by the emitter  202  to be sensed by the sensor  204 . A controller and/or microprocessor analyzes a signal provided by the sensor  204  and determines a location of the object  212  upon the touch surface  206  as a function of time. This analysis is interpreted by the processor to interpret gestures of the user in a context of software executing upon the controller and/or microprocessor. The touch surface  206  is formed of a material which is at least partially transparent to light waves emitted by the emitter  202 , whereby light emitted may reflect from the object  212  positioned upon the touch surface  206  to be received at the sensor  204  positioned below the touch surface  304 . 
     The term specular reflection is used to mean the mirror-like reflection of light from a surface, in which light from a single incoming direction (a ray) is reflected into a single outgoing direction. The direction of incoming light (the incident ray), and the direction of outgoing light reflected (the reflected ray) make the same angle with respect to the surface normal, thus the angle of incidence equals the angle of reflection and that the incident, normal, and reflected directions are coplanar. 
     The reliance of specular reflection from the object  212  to detect movement of the object  212  upon the touch surface  304  results in various short comings. For example, ambient lighting, such as sun light, can affect these conventional optical systems and hinder their performance. Also, residue, such as water, oil, lotion, etc., on the object or the touch surface can also adversely affect the performance of conventional optical sensors as well. Even further, items, such as gloves, can result in these conventional optical sensors performing poorly as well. Additionally, because light is required to pass through the touch surface, the sensor cover of conventional optical sensors is limited to translucent materials and to a limited amount of colors. 
     Optical Interference Based User Input Device 
     As will be discussed in greater detail below, various examples of the present invention overcome these and other problems of conventional optical sensors by providing an optical interference based user input device. In one or more examples, the optical interference based user input device comprises a sensor, such as an image sensor, that utilizes one or more patterns that generate a set of interference patterns such as, but not limited to, moiré patterns, when the one or more patterns are displaced with respect to each other. 
     For example, as the user interacts with the touch surface of the input device, the touch surface (or sensor cover) is deformed and/or displaced. The sensor detects and any changes in the existing interference patterns and/or the creation of any interference patterns created as a result of this deformation/displacement. A controller and/or processor coupled to the sensor is then able to determine a user desired action, such as a selection and/or a movement, based on the detected interference pattern or sequence of interference patterns. Therefore, because the sensor of one or more examples of the present invention utilizes interference patterns instead of detecting light reflections, the sensor is not adversely affected by ambient light and residue. Also, the touch surface and/or sensor cover can be made of a variety of materials and colors and is no longer limited to being transparent. 
     The input device  102  is now discussed in more detail in accordance with one or more examples of the present invention.  FIG. 3  shows a top-side view of the input device  102 . The input device  102 , in one example, comprises a sensor cover  302 . The sensor cover  302 , in this example, comprises a top portion  304  (also referred to herein as “touch surface  304 ”) with which a user interacts. For example, the user can place his/her finger(s) (or any other object) on the touch surface  304  and perform one or more gestures thereon. In other words, the sensor cover is not moved when indicating a desired movement. In another example, the user is able to move the sensor cover  302  to indicate a desired movement. For example, the user is able to move, tilt, and/or depress the sensor cover  302  to indicate a desired movement. The input device  102  further comprises an optional retaining member  306  that surrounds the sensor cover  302  and retains the sensor cover  302  over a sensor  401  ( FIG. 4 ), that is capable of sensing finger motion such as, but not limited to an optical sensor.  FIG. 2  also shows a circuit board  308  that includes connections which send and receive signals to and from the sensor  401 . 
       FIG. 4  shows a cross-sectional view of the input device  102 . It should be noted that only the touch surface  304  of the sensor cover  302  is shown in  FIG. 4  for simplicity. In particular,  FIG. 4  shows a sensor module  401  comprising a light emitter  402  (which can include an optional emitter lens (not shown)), an optional receiver lens  404 , and an interference pattern detecting module (IPDM)  406  such as, but not limited to, an image sensor. In one example, the light emitter  402  is an infrared light, a light emitting diode, or any other component that emits any type of light. Also, the receiver lens  404 , in one example, is disposed above the IPDM  406  and focuses images onto the IPDM  406 . In the example shown in  FIG. 4 , the light emitter  402  and the IPDM  406  are coupled to one or more circuit board  308 , which includes connections (not shown) that send and receive signals to and from the sensor  401 . The circuit board  308  is coupled to a controller  1302  and/or microprocessor  1416 . (See  FIGS. 13 and 14 ). 
       FIG. 4  also shows that one or more translucent layers or films  408  are disposed above the sensor  401 . In one example, this translucent layer  408  comprises a translucent material, such as (but not limited to) plastic film, glass film, etc., that allows light emitted from the emitter  402  to pass through a bottom surface  410  of the translucent layer  408  up through a top surface  412  of the translucent layer  408 . In one example, this translucent layer  408  comprises at least a first set of patterns  414  disposed thereon. For example, a non-reflective material, such as (but not limited to) ink, paint, etc., can be disposed on or within the translucent layer  408  in a given pattern(s) such that sensor  401  detects a given image associated with the first set of patterns  414  when the input device  102  is in a first state (e.g., not being interacted with by the user). It should be noted that other methods of creating/disposing the first set of patterns  414  on the translucent layer  408  are applicable as well. 
       FIG. 4  further shows that the touch surface  304  is disposed above the top surface  412  of the translucent layer  408 . In particular, a bottom surface  416  of the touch surface  304  faces the top surface  412  of the translucent layer  408 . In one example, at least a portion  418  of the bottom surface  416  of the touch surface  304  is either reflective and/or comprises at least a second set of patterns  420 . For example,  FIG. 4  shows that this portion  418  comprises a second set of patterns  420  that is either a reflection of the first set of patterns  414  on the translucent layer  408  and/or is a separate pattern(s) disposed on the bottom surface  416  of the touch surface  304 . In an example where the second set of patters  420  are a reflection of the first set of patterns  414 , the second set of patterns can be reflected through the translucent layer  408  and detected by the IPDM  406 . 
     It should be noted that in the example where the second set of patterns  420  are disposed on the bottom surface  416 , the second set of patterns  420  can either be different from or substantially similar to the first set of patterns  414 . Alternatively, the light emitted by the emitter  402  can project the first set of patterns  414  onto the bottom surface  416  of the touch surface  304 . In one example, the first and second set of patterns  414 ,  420  are configured such that when one set of patterns is displaced with respect to the second set of patterns, one or more interference patterns such as, but not limited to, a moiré pattern is created. In one example, the IPDM  406  detects this third set of patterns as changes in the first set of patterns  414 . These interference patterns are discussed in greater detail below. 
     In one example, the light emitter  402  is configured to illuminate at least a portion of the translucent layer  408  and at least a portion of the bottom surface  416  of the touch surface  304 , as indicated by the solid arrows  403 ,  405 . The IPDM  406 , in one example, is also configured to capture an image corresponding to at least a portion of the translucent layer  408  and/or at least a portion of the bottom surface  416  touch surface  304 . In other words, at least a portion of the translucent layer  408  and/or at least a portion of the bottom surface  416  of touch surface  304  are within a field of view of the IPDM  406 , as indicated by the dashed arrows  407 ,  409 . 
       FIG. 4  also shows that a set of resilient spacers  422 ,  424 ,  426 ,  428  are disposed between and abut the bottom surface  416  of the touch surface  304  and the top surface  412  of the translucent layer  408 . These spacers  422 ,  424 ,  426 ,  428  define a first distance, D 1 , between the bottom surface  416  of the touch surface  304  and the top surface  412  of the translucent layer  408  when in a relaxed state, i.e., when the spacers are not being compressed by a force applied to the touch surface  304 , as shown in  FIG. 5 . The spacers  422 ,  424 ,  426 ,  428  also define a first distance, D 2 , between the bottom surface  416  of the touch surface  304  and the detector module  406  (including the optional receiver lens  404 ) when in a relaxed state, as shown in  FIG. 5 . The resilient spacers  422 ,  424 ,  426 ,  428  can comprise any type of resilient material and can be configured in various shapes and sizes. 
     In one example, the emitter  402  illuminates the first set of patterns  414  disposed on the translucent layer  408  and the second set of patterns  420  disposed on the bottom surface  416  of the touch surface  304 . This illumination allows the IPDM  406  to detect and capture an image comprising at least the first set of patterns  414 . In one example, the first and second patterns  414 ,  420  are situated with respect to each other such that when the touch surface  304  is in a relaxed state (i.e., not being interacted with), an interference pattern is not detected by the IPDM  406 . For example,  FIG. 6  shows one example of an image  602 , which corresponds to the touch surface  304 , captured by the IPDM  406  when the touch surface  304  is in a relaxed state, e.g., the distance between the bottom surface  416  of the touch surface  304  and the top surface  412  of the translucent layer  408  is at a first distance D 1 . In the example of  FIG. 6 , the IPDM  406  captures/receives an image  602  comprising only the pattern of the first set of patterns  414  since the first and second set of patterns  414 ,  420  have not been displaced with respect to each other. However, it should be noted that other configurations are applicable such that when the touch surface  304  is in a relaxed state the image  602  captured by the IPDM  406  comprises at least a portion of the first and second set of patterns  414 ,  420 . In the example of  FIG. 6 , the controller/microprocessor  1302 ,  1416  determines that the touch surface  304  is currently not being interacted with based on the image  602  captured/received by the IPDM  406 . 
     However, when a user places his/her finger or another object onto the touch surface  304  and applies a force, the touch surface  304  is deformed and/or displaced a given amount based on the amount of force being applied by the user, as shown in  FIG. 7 . Stated differently, the distance between at least a portion of bottom surface  416  of the touch surface  304  and at least a portion of the top surface  412  of the translucent layer  408  is at a second distance D 3 . For example, as can be seen in  FIG. 7 , at least the portion  702  of the touch surface  304  corresponding to the location of the user&#39;s finger or other object applying a force has been displaced/deformed. One or more of the resilient spacers  422  are also displaced/deformed as well. This displacement of the portion  702  of the touch surface  304  and the one or more spacers  422  defines a second distance, D 3 , between the bottom surface  416  of the touch surface  304  and the top surface  412  of the translucent layer  408  and at least a second vertical distance, D 4 , between the bottom surface  416  of the touch surface  304  and the IPDM  406  (including the optional receiver lens  404 ). 
     This displacement further results in at least a portion  704  of the second set of patterns  420  being displaced with respect to the first set of patterns  414 , as shown in  FIG. 7 . This displacement of at least the portion  704  of the second set of patterns  420  creates a third set of patterns  804  ( FIG. 8 ), such as an inference pattern, between the first and second patterns  414 ,  420 . For example,  FIG. 8  shows an image  802  captured by the IPDM  406  as the user is touching the portion  702  of the touch surface  304  discussed above with respect to  FIG. 7 . 
     As can be seen,  FIG. 8  shows that the image  802  comprises a first region  806  that has been changed, i.e., comprises an interference pattern  804  that is generated at a location in the image  802  that corresponds to the portion  702  of the touch surface  304  that the user is currently applying force/pressure to. It should be noted that the size and shape of the region  806  depicted in  FIG. 8  is shown for illustrative purposes only. This interference pattern  804  is created as a result of the portion  704  of the second set of patterns  420  being displaced (e.g., becoming opposed, rotated by a given angle, etc.) with respect to the first set of patterns  414 . For example,  FIG. 15  shows a second set of patterns  1504  being displaced with respect to a first set of patterns  1502 . As a result of this displacement, one or more interference patterns  1506 ,  1508  are created. It should be noted that the present invention is not limited to the interference pattern shown in  FIG. 15 . For example,  FIGS. 16-19  show additional examples of interference patterns  1600 ,  1700 ,  1800 ,  1900  comprising various configurations such as, a striped, circular, square, or serpentine configuration. It is assumed that the reader is familiar with the principles of interference patterns, such as moiré patterns, and, therefore, a more detailed explanation thereof will not be given. 
     The image  802  comprising the interference pattern  804  captured by the IPDM  406  or at least information associated therewith is then transmitted to the controller/processor  1302 ,  1416 . Because the image  802  captured by the IPDM  406  corresponds to the touch surface  304 , the controller/processor  1302 ,  1416  is able to determine the location on the touch surface  304  where the user has placed his/her finger(s) or object(s) based on the location of the interference pattern  804  in the image  802 . The controller/processor  1302 ,  1416  performs one or more actions, such as a selection and/or a movement of a cursor on the display. 
     As the user moves his/her finger/object across the touch surface  304 , other portions of the touch surface  304  become deformed/displaced similar to that shown and discussed above with respect to  FIG. 7 . This results in additional interference patterns being generated, the shape of an interference pattern(s) being changed, and/or the location of an interference pattern(s) being changed. These changes to interference patterns or the new interference patterns that have been generated are detected by the IPDM  406 , as shown in  FIG. 9 . As can be seen in  FIG. 9  the image  902  captured by the IPDM  406  shows that a second region  906  comprises a second interference pattern  904  as a result of the user moving his/her finger/object from the first location  702  on the touch surface  304  to a second location on the touch surface  304 . 
     In this example, the second region  906  in the image  902  corresponds to the second location on the touch surface  304  where the user has transitioned his/her finger/object to. The image  902  comprising the second interference pattern  904  captured by the IPDM  406  or at least information associated therewith is then transmitted to the controller/processor  1302 ,  1416 , similar to that discussed above. Then, based on the location of the second interference pattern  904  with respect to the first interference pattern  804 , the time lapse between the first interference pattern  804  being generated and the second interference pattern  904  being generated, or the like, the controller/processor  1302 ,  1416  is able to determine the direction, speed, and/or pattern of the user&#39;s movement across the touch surface  304 . The controller/processor  1302 ,  1416  can then perform one or more operations based thereon. For example, the controller/processor  1302 ,  1416  can move a cursor on the display, perform a scrolling operation, increase/decrease the cursor movement velocity, move an icon, etc. 
     In another example, the user is able to place two or more fingers or objects on the touch surface  304  at a first and second location, respectively. For example, the user can place his/her thumb and finger on the touch surface  304  and perform a “pinching” motion where the user brings his/her thumb and fingers together. When the user initially places his/her thumb and finger on the touch surface  304  a first portion of the touch surface  304  corresponding to the location of the user&#39;s thumb and a second portion of the touch surface  304  corresponding to the location of the user&#39;s finger become deformed/displaced, as discussed above with respect to  FIG. 7   
     Therefore, at least a first and a second portion of the second set of patterns  420  corresponding to the first and second portions of the touch surface  304  being deformed/displaced are also deformed/displaced. This displacement of the first and second portions of the second set of interference patterns  420  causes these portions to become displaced with respect to a corresponding portion of the first set of patterns  414 . This results in a third pattern, such as an interference pattern, to be detected by the IPDM  406  in a first region of the image and a second interference pattern in a second region of the image corresponding to the first and second location at which the user&#39;s thumb and finger have been placed. 
     For example,  FIG. 10  shows an image  1002  captured by the IPDM  406  that corresponds to the touch surface  304 . As can be seen in  FIG. 10 , a first interference pattern  1004  is detected by the IPDM  406  in a first region  1006  of the image  1002  and a second interference pattern  1008  is detected in a second region  1010  of the image  1002  corresponding to the first and second location at which the user&#39;s thumb and finger have been placed on the touch surface  304 , respectively. As the user moves his/her finger and thumb across the touch surface  304 , other portions of the touch surface  304  become deformed/displaced similar to that shown and discussed above with respect to  FIG. 7 . This results in additional interference patterns being generated and detected by the IPDM  406  in subsequent images  1102 , as shown in  FIG. 11 . 
       FIG. 11  shows additional interference patterns  1104 ,  1108  created in other regions  1106 ,  1110  of the image  1102  resulting from the user moving his/her finger and thumb from the first and second locations of the touch surface  304  discussed above with respect to  FIG. 10  to a new location corresponding to regions  1106  and  1110  shown in  FIG. 11 . Based upon the IPDM  406  detecting the interference patterns  1004 ,  1008 ,  1104 ,  1108  shown in  FIGS. 10 and 11  the controller/processor  1302 ,  1416  can then perform one or more operations based on the position of these interference patterns with respect to each other, the change in position between the first and second patterns and the third and fourth patterns, respectively, and the like. 
       FIGS. 20-23  show other examples of interference patterns being created/changed as a user interacts with the touch surface  304  of the input device  102 . For example,  FIG. 20  shows a set of interference patterns  2002  being created as a result of the user placing his/her finger on the touch surface  304 . As the user drags his/her finger in a horizontal direction across the touch surface  304 , the second set of patterns  420  are displaced with respect to the first set of patterns  414  resulting in the set of interference patterns  2002  also changing and/or moving, as shown in  FIG. 21 . As can be seen in  FIG. 21 , the changes/movement of the set of interference patterns  2002  correspond to the changes in location and movement of the user&#39;s finger across the touch surface  304 .  FIG. 22  shows another set of interference patterns  2202  being created as a result of the user placing his/her finger on the touch surface  304  and drags his/her finger in a vertical direction. As the user interacts with the touch surface  304  the set of interference patterns  2002  change and/or move, as shown in  FIG. 23 . The changes/movement of the set of interference patterns  2202  correspond to the changes in location and movement of the user&#39;s finger across the touch surface  304 . The IPDM  406  detects the set of interference patterns  2002 ,  2202  and changes thereto and the controller/processor  1302 ,  1416  can then performs one or more operations based thereon. 
     As can be seen, the input device  102  of one or more examples of the present invention overcomes the problems of conventional optical based user input devices by utilizing one or more sets of patterns  414 ,  420  to generate optical interference patterns corresponding to a user&#39;s interaction with the touch surface  304  of the input device  102 . Therefore, because the input device  102  comprises a sensor module  401  that utilizes interference patterns instead of detecting light reflections, the input device  102  is not adversely affected by ambient light and residue. Also, the touch surface  304  and/or sensor cover 302  of the input device  102  can be made of a variety of materials and colors are is no longer limited to being transparent. 
     Flow Diagram 
       FIG. 12  is a flow diagram for an optical interference based user input device management process  1200 . The optical interference based user input device management process  1200  manages the user input device and its operations based on the utilization and detection of optical interference patterns, as discussed above with respect to  FIGS. 1-11 . This optical interference based user input device management process  1200  is performed by the controller  1302  or processor  1416  discussed below. 
     The operational flow diagram of  FIG. 12  begins at step  1202  and continues directly to step  1204 . The IPDM  406 , at step  1204 , captures/receives a least one image  602  corresponding to a touch surface  304  of a input device  102 . The image  602  comprises at least a first set of patterns  414 . The controller  1302  or processor  1416 , at step  1206 , analyzes the image  602 . The controller  1302  or processor  1416 , at step  1208 , determines if the image comprises at least one interference pattern  804 . If the result of this determination is negative, the control flow returns to step  1204 . If the result of this determination is positive, the controller  1302  or processor  1416 , at step  1210 , determines that the user is interacting with the input device  102 . The controller  1302  or processor  1416 , at step  1212 , then performs one or more user input device operations based on the interference pattern(s) that has been detected in the image(s)  602 . The control flow then exits at step  1214 . 
     Controller 
       FIG. 13  shows one example of a controller  1302 . With further reference to  FIG. 13 , the input device  102  may, in one example, be provided with flexible connector wires  1304  which carry signals between the user input device and other circuits within the electronic device  100 . The input device  102  may be provided with internal electronics or circuits, not shown, which combine or prepare such signals before and or after transmission on connector wires  1304 . A connector, for example board to board connector  1306 , may be provided to electrically connect connector wires  1304  to a circuit board (not shown) within the electronic device  100 . Other wires  1308  convey the signals to the controller  1302 , which may prepare and process the signals for further processing elsewhere within the electronic device  100 , or wires  1308  may connect directly to a microprocessor  1416  ( FIG. 14 ) of the electronic device  100 . 
     Electronic Device 
       FIG. 14  is a block diagram of an electronic device and associated components  1400  in which the systems and methods disclosed herein may be implemented. In this example, an electronic device  1402  is a wireless two-way communication device with voice and data communication capabilities. Such electronic devices communicate with a wireless voice or data network  1404  using a suitable wireless communications protocol. Wireless voice communications are performed using either an analog or digital wireless communication channel. Data communications allow the electronic device  1402  to communicate with other computer systems via the Internet. Examples of electronic devices that are able to incorporate the above described systems and methods include, for example, a data messaging device, a two-way pager, a cellular telephone with data messaging capabilities, a wireless Internet appliance, a tablet computing device or a data communication device that may or may not include telephony capabilities. 
     The illustrated electronic device  1402  is an example electronic device that includes two-way wireless communications functions. Such electronic devices incorporate communication subsystem elements such as a wireless transmitter  1406 , a wireless receiver  1408 , and associated components such as one or more antenna elements  1410  and  1412 . A digital signal processor (DSP)  1414  performs processing to extract data from received wireless signals and to generate signals to be transmitted. The particular design of the communication subsystem is dependent upon the communication network and associated wireless communications protocols with which the device is intended to operate. 
     The electronic device  1402  includes a microprocessor  1416  (and/or the controller  1302  discussed above) that controls the overall operation of the electronic device  1402 . The microprocessor  1416  interacts with the above described communications subsystem elements and also interacts with other device subsystems such as non-volatile memory  1418  and random access memory (RAM)  1420 . The non-volatile memory  1418  and RAM  1420  in one example contain program memory and data memory, respectively. The microprocessor  1416  also interacts with the input device  102 , an auxiliary input/output (I/O) device  1422 , a Universal Serial Bus (USB) Port  1424 , a display  1426 , a keyboard  1428 , a speaker  1432 , a microphone  1434 , a short-range communications subsystem  1436 , a power subsystem  1438 , and any other device subsystems. 
     A battery  1440  is connected to a power subsystem  1438  to provide power to the circuits of the electronic device  1402 . The power subsystem  1438  includes power distribution circuitry for providing power to the electronic device  1402  and also contains battery charging circuitry to manage recharging the battery  1440 . The power subsystem  1438  includes a battery monitoring circuit that is operable to provide a status of one or more battery status indicators, such as remaining capacity, temperature, voltage, electrical current consumption, and the like, to various components of the electronic device  1402 . An external power supply  1446  is able to be connected to an external power connection  1448 . 
     The USB port  1424  further provides data communication between the electronic device  1402  and one or more external devices. Data communication through USB port  1424  enables a user to set preferences through the external device or through a software application and extends the capabilities of the device by enabling information or software exchange through direct connections between the electronic device  1402  and external data sources rather than via a wireless data communication network. 
     Operating system software used by the microprocessor  1416  is stored in non-volatile memory  1418 . Further examples are able to use a battery backed-up RAM or other non-volatile storage data elements to store operating systems, other executable programs, or both. The operating system software, device application software, or parts thereof, are able to be temporarily loaded into volatile data storage such as RAM  1420 . Data received via wireless communication signals or through wired communications are also able to be stored to RAM  1420 . As an example, a computer executable program configured to perform the optical interference based user input device management process  1200 , described above, is included in a software module stored in non-volatile memory  1418 . 
     The microprocessor  1416 , in addition to its operating system functions, is able to execute software applications on the electronic device  1402 . A predetermined set of applications that control basic device operations, including at least data and voice communication applications, is able to be installed on the electronic device  1402  during manufacture. Examples of applications that are able to be loaded onto the device may be a personal information manager (PIM) application having the ability to organize and manage data items relating to the device user, such as, but not limited to, e-mail, calendar events, voice mails, appointments, and task items. Further applications include applications that have input cells that receive data from a user. 
     Further applications may also be loaded onto the electronic device  1402  through, for example, the wireless network  1404 , an auxiliary I/O device  1422 , USB port  1424 , short-range communications subsystem  1436 , or any combination of these interfaces. Such applications are then able to be installed by a user in the RAM  1420  or a non-volatile store for execution by the microprocessor  1416 . 
     In a data communication mode, a received signal such as a text message or web page download is processed by the communication subsystem, including wireless receiver  1408  and wireless transmitter  1406 , and communicated data is provided the microprocessor  1416 , which is able to further process the received data for output to the display  1426 , or alternatively, to an auxiliary I/O device  1422  or the USB port  1424 . A user of the electronic device  1402  may also compose data items, such as e-mail messages, using the keyboard  1428 , which is able to include a complete alphanumeric keyboard, a telephone-type keypad or a “virtual” keyboard implemented as key images rendered upon a touchscreen display, in conjunction with the display  1426  and possibly an auxiliary I/O device  1422 . Such composed items are then able to be transmitted over a communication network through the communication subsystem. 
     For voice communications, overall operation of the electronic device  1402  is substantially similar, except that received signals are generally provided to a speaker  1432  and signals for transmission are generally produced by a microphone  1434 . Alternative voice or audio I/O subsystems, such as a voice message recording subsystem, may also be implemented on the electronic device  1402 . Although voice or audio signal output is generally accomplished primarily through the speaker  1432 , the display  1426  may also be used to provide an indication of the identity of a calling party, the duration of a voice call, or other voice call related information, for example. 
     Depending on conditions or statuses of the electronic device  1402 , one or more particular functions associated with a subsystem circuit may be disabled, or an entire subsystem circuit may be disabled. For example, if the battery temperature is low, then voice functions may be disabled, but data communications, such as e-mail, may still be enabled over the communication subsystem. 
     A short-range communications subsystem  1436  is a further optional component which may provide for communication between the electronic device  1402  and different systems or devices, which need not necessarily be similar devices. For example, the short-range communications subsystem  1436  may include an infrared device and associated circuits and components or a Radio Frequency based communication module such as one supporting Bluetooth® communications, to provide for communication with similarly-enabled systems and devices. 
     A media reader  1442  is able to be connected to an auxiliary I/O device  1422  to allow, for example, loading computer readable program code of a computer program product into the electronic device  1402  for storage into non-volatile memory  1418 . In one example, computer readable program code includes instructions for performing the pressure detecting user input device operating process  1200 , described above. One example of a media reader  1442  is an optical drive such as a CD/DVD drive, which may be used to store data to and read data from a computer readable medium or storage product such as computer readable storage media  1444 . Examples of suitable computer readable storage media include optical storage media such as a CD or DVD, magnetic media, or any other suitable data storage device. Media reader  1442  is alternatively able to be connected to the electronic device through the USB port  1424  or computer readable program code is alternatively able to be provided to the electronic device  1402  through the wireless network  1404 . 
     The present subject matter can be realized in hardware, software, or a combination of hardware and software. A system can be realized in a centralized fashion in one computer system, or in a distributed fashion where different elements are spread across several interconnected computer systems. Any kind of computer system—or other apparatus adapted for carrying out the methods described herein—is suitable. A typical combination of hardware and software could be a general purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein. 
     The present subject matter can also be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which—when loaded in a computer system—is able to carry out these methods. Computer program in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following a) conversion to another language, code or, notation; and b) reproduction in a different material form. 
     Each computer system may include, inter alia, one or more computers and at least a computer readable medium allowing a computer to read data, instructions, messages or message packets, and other computer readable information from the computer readable medium. The computer readable medium may include computer readable storage medium embodying non-volatile memory, such as read-only memory (ROM), flash memory, disk drive memory, CD-ROM, and other permanent storage. Additionally, a computer medium may include volatile storage such as RAM, buffers, cache memory, and network circuits. Furthermore, the computer readable medium may comprise computer readable information in a transitory state medium such as a network link and/or a network interface, including a wired network or a wireless network, that allow a computer to read such computer readable information. 
     Non-Limiting Examples 
     Although specific embodiments of the subject matter have been disclosed, those having ordinary skill in the art will understand that changes can be made to the specific embodiments without departing from the spirit and scope of the disclosed subject matter. The scope of the disclosure is not to be restricted, therefore, to the specific embodiments, and it is intended that the appended claims cover any and all such applications, modifications, and embodiments within the scope of the present disclosure.