Abstract:
Systems and methods for detecting a position of an object in a sensing region are disclosed. One system includes a position sensor having an opaque capacitive proximity sensor, a light source, and a light conductor coupled to the light source and at least partially disposed over the opaque sensor, the light conductor configured to transmit at least a portion of the light from the light source to generate driven light effects in the sensing region. The system further includes a processor configured to control production of the light, and a display configured to illustrate a digital representation based on the position. A method includes the steps of sensing a position of an object in the sensing region based on a conductive property of the object, controlling light produced by a light source, and generating driven light effects in the sensing region using at least a portion of the light.

Description:
REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 10/417,786, filed on Apr. 15, 2003. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    The present invention generally relates to position sensors such as touchpads, and more particularly relates to devices, systems and methods for producing light effects that change the appearance of position sensors. 
       BACKGROUND OF THE INVENTION 
       [0003]    Position sensors are used as input devices for computers, personal digital assistants (PDAs), media players, video game players, consumer electronics, cellular phones, payphones, point-of-sale terminals and the like. One common type of position sensor is the touchpad-type sensor, which can be readily found, for example, as an input device on many notebook-type computers. A user generally operates the touchpad by moving a finger, stylus or other pointer near a sensing surface to move a cursor or other indicator on a display screen. A capacitive or inductive proximity sensor and/or a resistive touch sensor within the device senses the position of the finger or pointer, and suitably relays an electrical and/or electronic indication of the position to the computer or other host. One example of a touchpad that is based on capacitive sensing technologies is described in U.S. Pat. No. 5,880,411, which issued to Gillespie et al. on Mar. 9, 1999. Position sensors have also been combined with liquid crystal display technologies to create touch sensitive displays for notebook-type computers, PDAs, point of sale terminals, automatic teller machines, kiosks and the like. 
         [0004]    Although position sensors have been widely adopted, designers continue to look for ways to improve the sensors&#39; appearance and functionality. In particular, difficulties have long been realized in illuminating or otherwise producing light effects on the sensor. Some touch-sensitive displays have been illuminated with backlighting from a fluorescent lamp or other source. This technique has several inherent disadvantages, however, most notably that the sensors used in such devices must typically be made transparent or translucent so that light is able to pass through the sensor to the observer&#39;s eye. Although such sensors may be fabricated from materials such as Indium Tin Oxide (ITO), these materials have generally been found to be disadvantageous in terms of cost, manufacturability, design flexibility, performance and the like. Moreover, ITO can be somewhat absorptive, thereby partially obscuring the display. Even further, ITO is frequently subject to wear and cracking in use, thereby limiting the lifetime of the sensor. 
         [0005]    Accordingly, it is desirable to provide a position sensor that is capable of producing a light effect that modifies the appearance of the position sensor. In addition, it is desirable to produce the light effect without requiring a transparent or translucent touch sensor. Moreover, it is desirable to create a position sensor that provides position-sensitive soft control and/or status indicator regions without requiring a liquid crystal or other display. Other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    Various embodiments of the invention provide position sensors for detecting a position of an object in a sensing region. An exemplary position sensor comprises an opaque capacitive proximity sensor configured to sense the position of the object in the sensing region based on a conductive property of the object. The position sensor further comprises a light source for producing light, and a light conductor coupled to the light source and at least partially disposed over the opaque sensor, the light conductor configured to transmit the light to generate driven light effects in the sensing region. 
         [0007]    Systems for responding to a position of an object in a sensing region are also provided. One exemplary system comprises position sensor comprising an opaque capacitive proximity sensor configured to sense the position of the object in the sensing region based on a conductive property of the object, a light source configured to produce light, and a light conductor coupled to the light source and at least partially disposed over the opaque sensor, the light conductor configured to transmit at least a portion of the light from the light source to generate driven light effects in the sensing region. The system also comprises a processor coupled to the light source and configured to control production of the light, and a display coupled to the position sensor and the processor, the display configured to illustrate a digital representation based on the position. 
         [0008]    Various other embodiments provide methods for detecting a position of an object in a sensing region. An exemplary method comprises the step of sensing, via an opaque capacitive proximity sensor, the position of the object in the sensing region based on a conductive property of the object. The method further comprises the steps of controlling, via a control system, light produced by a light source, and generating, via a light conductor coupled to the light source, driven light effects in the sensing region using at least a portion of the light. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Various aspects of the present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and 
           [0010]      FIG. 1  is a block diagram of an exemplary computing system including a position sensor capable of producing a light effect; 
           [0011]      FIGS. 2A-B  are perspective and side views, respectively, of an exemplary position sensor; 
           [0012]      FIG. 3A  is a perspective view of an exemplary light transmitting assembly suitable for use with a position sensor; 
           [0013]      FIG. 3B  is a side view of an exemplary position sensor including the light transmitting assembly of  FIG. 3A ; 
           [0014]      FIG. 3C  is a perspective view of an alternate embodiment of an exemplary light conductor; 
           [0015]      FIG. 4  is a top view of an exemplary light transmitting assembly capable of displaying a logo or other design; 
           [0016]      FIG. 5  is a flowchart of an exemplary process for controlling a position sensor; and 
           [0017]      FIGS. 6A-B  are perspective views of exemplary soft control implementations of a calculator and media player, respectively. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. 
         [0019]    According to various exemplary embodiments, a position sensor is provided with a light source and a light conductor having a light pipe and/or one or more optical fibers. The light conductor suitably transmits light across the position sensor, and light is scattered from the conductor to produce a light effect that is observable by a user and that alters the appearance of the position sensor. Examples of light effects include illuminating the position sensor, flashing a light, changing a color of a light, and the like. Because light is distributed by a light conductor, the light source may be placed in any location, and the need for backlighting is suitably reduced. Moreover, because light can be effectively conducted between the position sensor and the viewer&#39;s eye, the position sensor is no longer required to facilitate light transmission. Accordingly, the position sensor does not need to be made from expensive transparent materials, thereby improving the cost and performance of the position sensor. In a further embodiment, light scattering from the conductor can be arranged such that one or more status indicators, “soft buttons” and/or other “soft controls” are created on the sensor without the need for backlighting or separate display functionality. 
         [0020]    Although the various embodiments described herein frequently refer to “touchpads”, the term “touchpad” as used herein is intended to encompass not only conventional touchpad devices, but also a broad range of equivalent devices that are capable of detecting the position of a finger, pointer, stylus or other object. Such devices may include, without limitation, touch screens, touch pads, touch tablets, biometric authentication devices, handwriting or character recognition devices, and the like. Similarly, the terms “position” or “object position” as used herein are intended to broadly encompass absolute and relative positional information, and also other types of spatial-domain information such as velocity, acceleration, and the like, including measurement of motion in one or more directions. Various forms of positional information may also include time history components, as in the case of gesture recognition and the like. Accordingly, “position sensors” appropriately detect more than the mere presence or absence of an object and may encompass a broad range of equivalents. 
         [0021]    Turning now to the drawing figures,  FIG. 1  is a block diagram of an exemplary computing system  100  that includes a touchpad  102  or other position-sensing input device. Computing system  100  is any type of personal computer, portable computer, workstation, personal digital assistant, video game player, telephone, media player or other device capable of accepting input from a user and of processing information. Accordingly, the various embodiments of computing system  100  may include any type of controller or processor  112 , memory  110 , display  114 , and input/output (I/O) interface  106  communicating via a bus  108 , network or other interconnection. Touchpad  102  may be connected to system  100  via I/O interface  106  using any type of connection (e.g. a PS/2, Universal Serial Bus (USB) or other type of connection), or may be directly coupled to bus  108  as appropriate. 
         [0022]    Touchpad  102  is sensitive to the position of a finger  104 , stylus or other object within a sensing region  103 . “Sensing region”  103  as used herein is intended to broadly encompass any space above, around, in and/or near touchpad  102  wherein the sensor of the touchpad is able to detect a position of the object. In a conventional embodiment, sensing region  103  extends from the surface of the sensor in one or more directions for a distance into space until signal-to-noise ratios prevent object detection. This distance may be on the order of centimeters or more, and may vary significantly with the type of position sensing technology used and the accuracy desired. Accordingly, the size and exact locations of the particular sensing regions  103  will vary widely from embodiment to embodiment. 
         [0023]    In operation, touchpad  102  suitably detects a position of finger  104  or other object within sensing region  103 , and provides electrical or electronic indicia of the position to interface  106 . Interface  106  suitably forwards the position indicia to processor  112  via bus  108 . Processor  112  appropriately processes the indicia to accept inputs from the user, to move a cursor or other object on display  114 , or for any other purpose. In a further embodiment, touchpad  102  suitably includes a light source that is capable of creating a light effect that alters the appearance of touchpad  102  in response to instructions from processor  112  and/or interface  106 , or as a function of user inputs detected within sensing region  103 , as appropriate, and as described more fully below. 
         [0024]    With reference now to  FIGS. 2A and 2B , an exemplary touchpad  102  suitably includes a circuit board or other substrate  202  supporting a sensor  204 . Touchpad  102  also includes a light source  206  that includes one or more light producers  206 A-D, as well as a light conductor  208  for transmitting light across the outer face of sensor  204 . The various components of touchpad  102  may be affixed together using any type of adhesive (e.g. epoxy, tape, pressure-sensitive adhesive and/or the like), or using any other joining technique. 
         [0025]    Sensor  204  is any capacitive, resistive, inductive or other type of sensor that is capable of detecting the position of a finger, stylus or other object, as described above. Exemplary sensors  204  include the various sensors produced by Synaptics Inc. of San Jose, Calif., which appropriately detect a one dimensional, two dimensional or multi-dimensional position of an object using capacitive or inductive coupling. 
         [0026]    As used herein, the term “light source” is intended to broadly encompass any device or combination of devices capable of providing light. In an exemplary embodiment, light source  206  is made up of one or more light producers  206 A-D. Light producers  206 A-D are any devices or components capable of providing any type of light, including any fluorescent, incandescent, coherent, stereoscopic, holographic or other source of light. Examples of various light producers  206 A-D include light emitting diodes, light bulbs, vertical cavity surface emitting lasers (VCSELs), fiber light sources and/or the like. In one exemplary embodiment, light providers  206 A-D are light emitting diodes such as those available from, for example, Agilent Technologies of Palo Alto, Calif. and other suppliers. 
         [0027]    Light conductor  208  is any light transmission medium capable of conducting light emitted from one or more light producers  206 A-D and/or of scattering light to make the light visible to the user. In various embodiments, light conductor  208  is a “light pipe” formed from plastic, glass or the like. Light pipes are available from, for example, Global Lighting Technologies of Brecksville, Ohio, as well as from Teledyne Lighting and Display Products of Los Angeles, Calif. and many others. Various light conductors and light conducting techniques are described, for example, in Application Brief I-003, “Light Guide Techniques Using LED Lamps” dated Dec. 7, 2001 and available from Agilent Technologies. In various embodiments, light conductor  208  is a custom light pipe that transmits light from light producers  206 A-D across a surface of touchpad  102  as appropriate. Although conventional “ideal” light pipes merely transmit light with little or no scattering effect, some or all of light conductor  208  may be designed to be “leaky” in the sense that light is allowed to escape to produce a light effect and thereby alter the appearance of the position sensor using the techniques described above and below. Accordingly, various light conductors  208  may be designed such that portions of the conductor are “ideal” (or approximately ideal, scattering only very small amounts of light), and such that light is otherwise scattered from only a portion of the light conductor to produce the desired effect. In an exemplary embodiment of a touchpad  102 , light conductor  208  may be implemented with a glass or plastic light pipe with a thickness on the order of about one millimeter and an area of about 37 mm×50 mm or so to cover the surface of a conventional sensor  204 , although light conductors having widely varying dimensions could be constructed in alternate embodiments. Other embodiments of light conductor  208  may include one or more light pipes, one or more optical fibers, step index fibers, prisms, and/or other light transmission media, which may be used in place of or in conjunction with one or more light pipes. 
         [0028]    In the exemplary embodiment shown in  FIGS. 2A-2B , light conductor  208  is appropriately located between sensor  204  and the sensing region  103  of touchpad  102 . Light conductor  208  may overlap either sensor  204  and/or sensing region  103  in whole or in part, and may not be perfectly situated between sensor  204  and sensing region  103  in all embodiments. Nevertheless, because light is brought in front of sensor  204  by light conductor  208 , the need to make sensor  204  transparent/translucent is significantly reduced, since light is no longer required to pass through sensor  204  to reach the viewer&#39;s eye. 
         [0029]    Light conductor  208  may also include one or more scattering elements (not shown in  FIGS. 2A-B ) for scattering, diffracting and/or dissipating light from light conductor  208 , as described more fully below. Light transmitted within light conductor  208  may be scattered from the surface and/or from the bulk of the conductor by providing scattering elements such as protrusions, depressions, textures, materials, gaps, gratings, labels, etchings and/or the like on, in or next to conductor  208 . Surface scattering, for example, may be implemented by etching, abrading, embossing, printing or otherwise forming a scattering pattern on a top, bottom, side and/or end face of conductor  208 . Similarly, bulk-type scattering could be implemented by placing pockets of plastic, glass, fibers, paint, air or other materials within the volume of light conductor  208 , by placing wavelength-sensitive gratings within conductor  208 , or by any other technique. By selectively placing scattering elements in a pattern with respect to light conductor  208 , light can be scattered from selected portions of conductor  208  to create various visual effects, including the “soft controls” and/or status indicators described below. 
         [0030]    Touchpad  102  may also include an optional face sheet  210  to protect the various components of touchpad  102  from moisture, contaminants and the like, and to provide an appropriate touch surface  212  for touch inputs. Face sheet  210  is typically a mostly (but not perfectly) smooth surface to provide users with an appropriate glide feel. In an exemplary embodiment, face sheet  210  is implemented with plastic (e.g. polyester) or any other suitable material. If a face sheet  210  is used, the material should be transparent or translucent such that light from light conductor  208  is able to escape from touchpad  102  to become viewable to the user. In an alternate embodiment, face sheet  210  is omitted entirely and the outer surface of light conductor  208  is appropriately textured to provide a desired touch surface  212  for touch inputs. In a further embodiment, the outer surface of light conductor  208  may be rough or otherwise appropriately textured to simultaneously provide surface light scattering and a desirable touch surface  212  for touchpad  102 . 
         [0031]    In addition to supporting sensor  204 , substrate  202  may also support a processor  214 , memory  216  and/or other control circuitry, as best seen in  FIG. 2B . The various circuitry components appropriately communicate with sensor  204  using digital or analog electrical signals provided through conventional vias or other electrical connections through or around substrate  202 . The particular control circuitry used varies widely from embodiment to embodiment, but in exemplary embodiments processor  214  is a model T1004, T1005, T100X or other microcontroller produced by Synaptics Inc. of San Jose, Calif. Similarly, memory  216  may be implemented with any random access memory (RAM), read only memory (ROM), flash memory, magnetic or optical storage device, or any other digital storage medium. Alternatively, the logical functions of memory  216  may be incorporated into processor  214  such that a physically separate memory device  216  may not be present in all embodiments. In many embodiments, memory  216  suitably stores digital instructions in any software or firmware form that are executable by processor  214  to implement the sensing and control functions described herein. 
         [0032]    In operation, sensor  204  is operable to sense user inputs correlating to the position of a finger or other object in proximity to touch surface  212 . Sensing region  103  encompasses the volume in which touchpad  102  is able to distinguish the signal effect of the finger or other object from background noise. Objects are detected within sensing region  103  using conventional capacitive, inductive, resistive or other sensing techniques. Alternatively, objects may be detected using temperature, pressure, force, optical energy, acoustic energy or any other parameter. In an exemplary embodiment, object position is sensed in two dimensions (e.g. X and Y coordinates) using conventional capacitive sensing techniques. In such embodiments, digital positional indicia may be provided from processor  214  to computing system  100  ( FIG. 1 ), as appropriate. 
         [0033]    Light effects may be produced on touchpad  102  by any technique. In an exemplary embodiment, light producers  206 A-D are activated to produce light  218 A that propagates through light conductor  208  as appropriate. One or more of light producers  206 A-D may be activated upon power up of touchpad  102 , in response to control signals from processor  214  or any other source, or according to any other technique. In the embodiment shown in  FIG. 2B , light producers  206 A-D are spatially arranged to initially direct emitting light away from sensor  204 , with reflective edges  220 A-B of light conductor  208  reflecting light  218 A-D toward the bulk of conductor  208 . Light  218  is scattered from conductor  208  according to any surface and/or bulk scattering technique to thereby produce a visible light effect that alters the appearance of touchpad  102 , as appropriate. 
         [0034]    The various light effects that may be produced from touchpad  102  vary widely from embodiment to embodiment. By controlling the various light producers  206 A-D from processor  214  (or computing system  100  or another controller) and/or by designing appropriate scattering elements in proximity to light conductor  208 , numerous light effects may be implemented even on a single touchpad  102 . Light producers  206 A-D may be selectively activated or controlled, for example, to produce desired light effects in response to varying user inputs or status conditions of touchpad  102 , and/or to reflect user preferences, on-screen events, processing modes for computing system  100 , or the like. Other light effects that may be produced include uniform or non-uniform (e.g. with certain portions lighted more brightly than others) lighting of surface  212  or sensing region  103 . Alternatively, one or more light producers  206 A-D may be intermittently activated or varied in light intensity to produce a flashing, strobing or other temporal variation effect, or different light producers  206 A-D may be selectively activated or controlled to produce light  218  of different colors, wavelengths and/or intensities. Various additional light effects are described more fully below. 
         [0035]    Light conductor  208  need not be integrally formed within touchpad  102 . With reference now to  FIG. 3A , an exemplary light conductor assembly  300  that may be integrally formed within a touchpad  102  or provided as a separate assembly suitably includes light sources having one or more light producers in optical communication with a light conductor  208 . Light sources  206  shown in  FIG. 3A  each include a single right angle mount light emitting diode (LED), although other numbers, types and combinations of light producers could be used in alternate embodiments. Light sources  206  suitably produce light  218  that propagates through light conductor  208  and that is scattered by scattering elements  302 . Assembly  300  may be provided as an add-on component, for example, to provide light effect functionality to existing touchpad sensors. 
         [0036]    In the embodiment shown in  FIG. 3A , scattering elements  302  are indentations formed in a bottom surface of conductor  208 , although additional or other scattering elements could be used in alternate embodiments. As shown in  FIG. 3A , scattering elements  302  are shown to be smaller and/or less densely located near light sources  206 , with larger and/or more densely situated scattering elements  302  located further away from light sources  206 . Because this arrangement of scattering elements  302  provides the greatest amount of scattering in the portions of conductor  208  where the least amount of light is propagating, the result may be an approximately uniform scattering of light  318  emanating across surface  212  of touchpad  102 . An optional reflection sheet  320  may also be provided to further enhance light scattering across light conductor  208 , and a face sheet  210  (not shown in  FIG. 3A ) may also be provided to further enhance the functionality and desirability of assembly  300 .  FIG. 3B  shows an exemplary touchpad  102  that includes light conductor assembly  300  providing light  218  from right-angled light sources  206  to light conductor  208 , as appropriate. Again, assembly  300  may not be integrally formed within touchpad  102 , but may be attached to sensor  204  using one or more adhesives, mechanical clamps, mechanical fasteners or other suitable attachment techniques. 
         [0037]    Further, and with reference now to  FIG. 3C , light conductor  208  may be of any shape, and light source  206  may be located in any orientation or position relative to sensor  204 . As shown in  FIG. 3C , an alternate embodiment of light conductor  208  suitably conducts light from light source  206  to a desired location, surface or area in proximity to sensor  204 . This design flexibility allows wide variability in the relative spatial positioning of light source  206  and sensor  204 , as well as the other components of various position sensors. Light source  206  may be located, for example, underneath substrate  202 , as a separate component from touchpad  102 , or in any other suitable location in or near computing system  100 . Accordingly, light source  206  need not be integrally formed with touchpad  102 . 
         [0038]    With reference now to  FIG. 4 , an alternate embodiment of a light conductor assembly  300  suitably includes a logo, status indicator, ornamental design or other pattern  402  in place of or in addition to scattering elements  302  ( FIG. 3A ). Pattern  402  may be etched, beveled, embossed or otherwise formed in or on any surface of light conductor  208 , or may be formed with a label, decal or the like on or near any surface of light conductor  208 . Alternatively, pattern  402  may be formed with in the volume of light conductor  208  using air gaps, particulates, bubbles and/or diffraction gratings present in light conductor  208 , or by any other technique. As light  218  is produced by one or more light producers (not shown) of light source  206 , pattern  402  suitably scatters light such that the logo or other pattern becomes visible to the user. The pattern may be seen, for example, on touch surface  212  ( FIG. 2A ), or elsewhere within sensing region  103  ( FIG. 1 ) using stereoscopic, holographic or other lighting techniques. 
         [0039]    In an exemplary embodiment, pattern  402  is formed with diffraction gratings that are sensitive to a wavelength, polarization or other component of light  218 . Alternatively, pattern  402  may be formed in or on light conductor  208  with light-sensitive paint or the like. Examples of light-sensitive paint include phosphorescent paint, fluorescent paint, wavelength-sensitive paint and the like. When the gratings and/or paint are exposed to light  218  having the appropriate properties, at least a portion of the light is scattered, absorbed and/or emitted by the grating and/or paint so that the pattern becomes visible to the user. Further, multiple patterns  402  may be present within various embodiments, with different light producers (not shown) of light source  206  being activated to produce light of differing wavelengths and/or polarizations to illuminate the various patterns at desired times. In this manner multiple patterns  402  may be produced by varying and/or modulating the intensity, frequency, direction, location and/or polarization of light produced by any particular light source  206 , or by selectively activating different light sources to produce the desired light effects. Different patterns  402  may include logos, ornamental designs, status indicators and/or “soft controls” that demark particular portions of sensing region  103  for special purposes. These soft controls may include buttons, sliders, character input regions, and the like. 
         [0040]      FIG. 5  is a flowchart of an exemplary process  500  for controlling and operating a position sensor that includes soft control functionality. While many of the functions described in  FIG. 5  may be computer-implemented using software or firmware instructions,  FIG. 5  is intended to illustrate various exemplary functions in logical form, and is not intended to present a literal implementation of a software routine. Accordingly, the various modules, functions and routines shown in  FIG. 5  may be enhanced, eliminated and/or differently organized in the many alternate practical embodiments. The various steps and modules set forth in process  500  may be implemented using any computer language, modules, applications, instructions or the like, and may be stored permanently or temporarily in memory  216  or in any other digital storage medium including a floppy disk, CD-ROM, RAM, ROM, optical or magnetic mass storage device, or the like. The instructions used to implement various portions of process  500  may also be transmitted as modulated signals on carrier waves transmitted across any communications medium such as a digital network, wireless link, or the like. 
         [0041]    With reference now to  FIG. 5 , an exemplary process  500  for controlling a touchpad  102  ( FIG. 1A ) or other position sensor suitably includes the broad steps of controlling a light source (step  502 ) to produce an appropriate light effect (step  503 ), sensing user input corresponding to the position of an object (step  504 ), processing any soft control functionality (steps  506 ,  508 ,  510 ), modifying the light effect produced (steps  512 ,  513 ,  515 ), and/or disabling the soft control (step  516 ,  520 ) as appropriate. 
         [0042]    Enabling the soft control (step  501 ) suitably initiates a process  500  that begins by activating and/or controlling light source  206  as appropriate (step  502 ). One or more LEDs or other light producers  206 A-D ( FIGS. 2A-B ) may be activated or deactivated, for example, or otherwise controlled to produce a desired light effect (step  503 ). As described above, light producers  206 A-D may be activated via a control signal provided by processor  214  ( FIG. 2B ), via computing system  100  through I/O interface  106  ( FIG. 1 ), or by any other technique. Each of the light producers  206 A-D present in a particularly embodiment may be activated in response to any stimulus, including a user selection of an operating mode for touchpad  102 , an event occurring within an application executing on computer system  100  ( FIG. 1 ), a particular input received by sensor  204  ( FIGS. 2A-B ,  3 B), or the like. 
         [0043]    Step  502  may also include providing light or light components with a desired wavelength, polarization and/or intensity to produce a desired light effect on touchpad  102  (step  503 ). Various forms of gratings, paint and/or scattering elements are sensitive to particular wavelength components, polarization components and/or locations of the light produced, such that certain patterns appear near light conductor  208  only when light of the appropriate parameters is produced. Light components may be varied in any manner, including by controlling a variable-input light source to modulate the intensity, frequency, color or another component of light produced, or by activating and/or deactivating one or more light producers in different positions or capable of providing light having the appropriate parameters to produce the desired light effects. To activate a soft control, for example, tuned diffraction gratings and/or light-sensitive paint may be used to create a pattern  402  defining the control. When light of the particular characteristics is produced, the soft control becomes visible in sensing region  103 . 
         [0044]    Detecting a user input (step  504 ) suitably involves obtaining position-related information about the object at sensor  204 . The position may be sensed and processed using, for example, conventional position sensing techniques such as those set forth in U.S. Pat. No. 5,880,411, referenced above. In a capacitive position sensor, for example, capacitive coupling between sensor  204  and the object in the sensing region remains possible even when light conductor  208  is disposed between sensor  204  and the object  104  being sensed. In other embodiments, position-related information may be obtained using inductive techniques, resistive techniques or the like. Positional information may be obtained in one or more directions using any conventional technique presently known or subsequently developed. 
         [0045]    In an exemplary embodiment, touchpad  102  returns a unique result to computing system  100  if the user&#39;s input corresponds to an enabled soft control (step  506 ). Activating a soft button, for example, may result in a particular response from touchpad  102  and/or computing system  100 . Soft controls may include buttons, sliders, character or gesture recognition regions, biometric observation regions, or the like. In an exemplary embodiment, a soft button is provided on a portion of a touchpad  102  to perform a task (e.g. open an application) on system  100 . If the user&#39;s finger (or other object sensed) is identified in the soft control portion of sensing region  103 , then an appropriate result may be provided (step  508 ) to computing system  100  to indicate that the “button” has been activated. Conversely, the portions of touchpad  102  outside of the soft control may retain conventional pointing functionality, so inputs outside of the soft control pattern  402  appropriately result in no soft control results (e.g. conventional positional outputs) being provided to computing system  100  (step  510 ). 
         [0046]    In various embodiments, the sensed position of the object may be used to modify the light effect produced (steps  512 ,  513 ,  515 ). If the light effect is to be modified (step  512 ), light source  206  is appropriately controlled (step  513 ) to produce the desired effect (step  515 ), as described above. Touching or tapping a soft control button, for example, may activate a light effect that reveals another set of soft controls. Alternatively, the light effect could simply be flashed, the color of the light could be changed, or any other light effect could be produced (step  515 ). In one embodiment, touchpad  102  may be used to estimate the pressure of a touch on touch surface  212 . Pressure is sensed, for example, by tracking changes in the surface area of touch surface  212  that is in contact with a user&#39;s finger, since greater pressure typically results in increased deformation of the user&#39;s finger, and therefore a greater surface area touched. This information could be used to vary the color of the light effect, for example, or to produce a light effect only on the portion of touch surface  212  that is in contact with the user&#39;s finger. Further, the position, brightness, color or other aspect of the effect could be adjusted as a function of and/or in response to the sensed position of the object. As such, a wide array of light effects could be produced in various alternate embodiments. Moreover, light effects could be modified (step  514 ) in response to stimuli other than user input. Data received from computing system  100  or any other external source, for example, could be used to place touchpad  102  into a desired input mode with a corresponding light effect, visible pattern  402  and/or set of soft controls. Some or all light producers of light sources  206  may be further deactivated (steps  516 ,  520 ) in response to positional information or external factors (e.g. system status, etc) as appropriate. Feedback to the user could also be provided from display  114  ( FIG. 1 ), an audio speaker associated with touchpad  102  or computing system  100  ( FIG. 1 ), and/or any other source. In an embodiment that provides soft control buttons corresponding to the buttons of a calculator, for example, an audible sound from computing system  100  could be produced to indicate that the user had activated a soft button. Many other types of feedback may be produced, and will vary widely from embodiment to embodiment. 
         [0047]    Soft controls may be disabled using any technique (steps  516 ,  520 ). In an exemplary embodiment, a user taps a soft button or otherwise activates a soft control. In another exemplary embodiment, computing system  100  instructs touchpad  102  to disable the soft control. 
         [0048]    Exemplary implementations of touchpads  102  having soft controls are shown in  FIGS. 6A and 6B , respectively.  FIG. 6A  shows an exemplary calculator implementation with various soft buttons corresponding to the various calculator functions.  FIG. 6B  shows an exemplary media player implementation whereby soft controls are used to play, pause, forward or reverse the media being played, as appropriate, and/or to implement a volume slider and/or other controls. As shown in  FIGS. 6A-B , multiple soft controls may be placed on a single touchpad  102 , and indeed multiple sets of soft controls may be activated at different times using the grating and/or wavelength/polarization sensitivity techniques described above, by activating different light providers  206 A-D, or by any other technique. As mentioned above, light effects produced on a touchpad  102  are not limited to soft controls, but may alternatively include variations in light color or intensity, status indicators, ornamental designs, logos and the like. 
         [0049]    Accordingly, there are provided numerous systems, devices and processes for producing light effects that alter the appearances of touchpads and other position sensors. While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.