Patent Publication Number: US-2010126784-A1

Title: Continuously variable knob input device

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to user interfaces for electronic devices and more particularly to a continuously variable knob input device. 
     BACKGROUND OF THE INVENTION 
     The market for electronic devices having user interfaces, for example, avionic equipment including radios and navigation equipment, computer monitors, televisions, cell phones, personal digital assistants (PDA&#39;s), digital cameras, and music playback devices, is very competitive. Manufactures are constantly improving their product with each model in an attempt to cut costs and production requirements. 
     In many electronic devices, data input devices, for example a knob (or dial), provide intuitive input from the user to data processing devices. Knobs are especially useful in electronic devices where other input devices typically occupy much more area. In communication devices, a knob may be used, for example, to adjust audio volume or visual intensity or change frequencies, or in navigation equipment to adjust a moving map. 
     Knobs typically are a material constructed of plastic, rubber, or metal that protrudes from a panel and that is shaped for easy grasp by the fingers and thumb of the user. Electrical circuitry coupled to the knob detects the movement of the knob or the end position of the knob after it has been rotated. This end position identifies the desired volume, intensity, or frequency, for example. In some known devices, the knob may be pushed to provide an on-off function. 
     Concentric duel knobs provide additional input from the user. Typically, the center knob protrudes further from the panel, so that either knob may be grasped by the user. The inner and outer knob of the concentric knobs may provide inputs for different selectable functions, or may provide a “course” and “fine” adjustment for the same desired function. However, the course and fine adjustment provided by these known knobs may not be calibrated for the ideal increments for a particular user or function. 
     Touch panels are another type of input device. There are many different types of touch panels, including capacitive, resistive, infrared, and surface acoustic wave. All of these technologies sense the position of touches on the device. The device generally includes a surface area across which a finger is moved to a desired position to identify a coordinate, for example, an item for selection. 
     It has been previously been disclosed in U.S. Pat. No. 6,492,979 to use a combination of capacitive touch screen and force sensors to prevent false touch. This disclosure however complicates the sensor interface and can not sense multiple touch forces at the same time. It has also been proposed in U.S. Pat. No. 7,196,694 to use force sensors at the peripherals of the touch screen to determine the position of a touch. This disclosure however does not offer a capability of multi-touch. It has been proposed in U.S. Pat. No. 7,321,361 to use a coordinate input device having a convex shape for providing such feedback to the user; however, the application of a force is sensed with a mechanical switch. Furthermore, touch screens occupy a large area on the electronic device. 
     Accordingly, it is desirable to provide a knob that senses the position of fingers thereon and may also sense force and movement of the fingers on the knob. Furthermore, 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 this background. 
     BRIEF SUMMARY OF THE INVENTION 
     An input device includes a knob having a rigid material defining an axis and having a surface opposed to the axis. Touch sensing layers are disposed on the surface that sense the position of one or more fingers applied thereto, the touch sensing layers providing a sensed signal indicative of the position of the fingers. An electronic device is coupled to receive the sensed signal and provides a gain signal based on the position of the fingers on the touch sensing layers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and 
         FIG. 1  is a cross sectional side view of a knob in accordance with a first exemplary embodiment; 
         FIG. 2  is a top cut away view of the first exemplary embodiment taken along line  2 - 2  of  FIG. 1  having fingers placed thereon in a first position; 
         FIG. 3  is a perspective view of capacitive sensing layers as may be used with the first and second exemplary embodiments; 
         FIG. 4  is a block diagram of a device incorporating the exemplary embodiments; 
         FIG. 5  is a graph illustrating two inputs provided by the finger placement shown in  FIGS. 2 and 6 ; 
         FIG. 6  is a top cut away view of the first exemplary embodiment taken along line  2 - 2  of  FIG. 1  having fingers placed thereon in a second position; 
         FIG. 7  is a cross sectional side view of a knob in accordance with a second exemplary embodiment; 
         FIG. 8  is a side view of a knob in accordance with a third exemplary embodiment; and 
         FIG. 9  is a graph illustrating the input provided by the third exemplary embodiment of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description of the invention 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 theory presented in the preceding background of the invention or the following detailed description of the invention. 
     The knob of the exemplary embodiments includes a plurality of force and movement sensing layers encasing a rigid material and is shaped to be grasped by one or more fingers and a thumb of a user. The layers determine the position of the fingers and thumb thereon, and in some embodiments, also senses the direction (of turn), speed and/or acceleration of finger movement, and pressure applied by the fingers, for determining the output signal. As the fingers are applied to the knob, the position, movement, and amount of pressure is sensed, for example, by a matrix of conductors in the sensing layers. In one embodiment, the knob is free of moving parts resulting in cost and reliability advantages over mechanical knobs. The input provided by the knob could select a function or have a fixed gain curve or a dynamic gain curve based on the active function. The shape of the knob could have a shape representative of the gain curve. Optionally, one of the sensing layers, preferably the one adjacent the fingers, may comprise a texture that varies in proportion to the amount of pressure, resulting in a variable degree of ease in which the fingers moves across the surface and providing feedback to the fingers. 
     This knob input device may be used in many types of electronic devices, including avionics equipment such as communication or navigation devices, computers, mobile devices such as a personal digital assistant (PDA), and the like. 
     Referring to  FIG. 1 , a first exemplary embodiment includes a knob  102  securely disposed over an electronic device  104  and electronically coupled thereto by conductors  106 . Circuit  105  within the electronic device  104  interprets a signal on conductors  106 . Alternatively, the knob  102  may, for example, be deposed on a housing (not shown) in which the electronic device  104  resides. In accordance with the first exemplary embodiment, touch sensing layers  108  are disposed on the outer surface of the rigid material  110  of the knob  102  for detecting the placement of fingers on the knob  102  (as will be illustrated subsequently in  FIG. 2 ). The rigid material  110  may be, for example, plastic, rubber, or metal. 
     There are many different types of touch sensing technologies, including capacitive, resistive, infrared, and surface acoustic wave. In some embodiments, it would be desirable to have a touch sensing device that not only senses the position of the touch, but also the force applied to the touch screen. Force sensing provides an extra dimension of freedom in inputting: it can simplify the input process by enabling different combinations of positions and forces on the knob  102 . It also offers the possibility of discriminating against false touches by setting different force thresholds before a touch can register. An additional advantage is that force sensing is not limited to only finger touch as in the case of capacitive sensing, it also accept input from almost all other devices including gloves. It is also more tolerant to environmental noises such as EMI and dirt/oil on surface. 
     Referring to  FIG. 2 , a top cross sectional view taken along lines  2 - 2  of  FIG. 1  shows the first exemplary embodiment of the knob  102  having movement and force sensing layers  108  formed over rigid material  110  of the knob  102 . A protective layer  112  may be formed over the sensing layers  108  to protect the sensing layers  108  from scratching, dirt, and oil. The protective layer  112  may be any rigid material, but is preferably is a polymer. 
     The sensing layers  108  may sense changes in, for example, capacitance, resistance, infrared, or surface acoustic wave characteristics. The exemplary embodiment shown in  FIG. 3  senses changes in capacitance wherein the sensing layers  108  include conductive layers  302  and  306  separated by a dielectric layer  304 . The conductive layers  302  and  306  each comprise a patterned plurality of adjacent but separated conductive traces  308  and  310 , respectively. The conductive traces  308  are generally orthogonal to the conductive traces  310 , providing a matrix of pixels, or a plurality of intersections, for sensing a capacitance therebetween. As fingers touch or move across the knob  102 , the capacitance at each of the intersections of the traces  308 ,  310  experience a change in capacitance. The traces  308 ,  310  are preferably aligned in respective directions and have a pitch of 0.05-10 mm, (preferably 1.0 mm), a width less than the pitch but larger than 0.001 mm, a thickness of 1.0-1000 nm, (preferably 80 nm). The traces  308 ,  310  may be a conductive material, for example, indium tin oxide, zinc oxide, and tin oxide. A tab  312 ,  314  is electrically coupled to each trace  308 ,  310  for providing connection to circuitry  105 . 
     Though various lithography processes, e.g., photolithography, electron beam lithography, imprint lithography, ink jet printing, may be used to fabricate the knob  102  and especially the patterned conductive traces  308 ,  310 , a printing process is preferred. A variety of printing techniques, for example, Flexo, Gravure, Screen, and inkjet, may be used. 
     The sensing layers  108  also sense the pressure in a manner such as shown in U.S. Pat. Nos. 6,492,979 and 7,196,694, or in the document “Paper FSRs and Latex/Fabric Traction Sensors: Methods for the Development of Home-Made Touch Sensors”, by Rodolphe Koehly et al., Proceedings of the 2006 International Conference on New Interfaces for Musical Expression (NIME06), Paris, France, which are hereby incorporated by reference. For example, a conductive ink such as carbon black pigment may be mixed into a medium such as polyvinyl acetate, varnish, or liquid black inks. 
     By sensing this change in resistance due to pressure being applied to the sensing layers  108 , the selection of modes, or functions, such as selecting a particular gain curve, may be accomplished. By scanning the rows and columns of the conductive traces and mapping the capacitance of the materials at each intersection, a corresponding map of the coordinate input device may be obtained. This map provides both the position and the force of the corresponding touch. The placing of multiple fingers on the screen can be distinguished, thus enabling greater freedom of inputting. The amount of force of the touch may be used, for example, as a variable gain on the input. A light touch may indicate a high gain on the position output, while a hard touch would indicate a lower gain on the position output. Additionally, the amount of force could be used as a z-axis position or as a zooming control. 
     A knob  102  generally is a material that rotates about an axis  111 . The above embodiment allows for the sensing of finger placement and for movement of the fingers  120 ,  122  around the knob  102  (around the axis  111 ) without actual rotation of the knob  102  about the axis  111 . Additional input may also be provided by movement of the fingers  120 ,  122  in a direction in a direction other than rotationally, for example, parallel with the axis  111 , speed of the fingers  120 ,  122  in providing this movement, and different pressures exerted by the fingers  120 ,  122 . All of these variables may be used to select or adjust information received by a user. 
     While the embodiments described herein may be used in electronic devices in general, a block diagram of an electronic device  400  as an example using the knob input device  100  is depicted in  FIG. 4 . A controller  406  provides drive signals  410  to the knob input device  102  (more specifically the touch sensing layers  108 ), and a sense signal  404  is provided from the knob input device  102  to the controller  406 , which periodically provides a signal  408  of the distribution of pressure to a processor  412 . The processor interprets the controller signal  408 , determines a function in response thereto, and provides a signal  414  to a functional device  416 . Although the functional device  416  is shown in this exemplary embodiment, other types of devices or systems, such as a mapping system, may receive the signal  414 . 
     In operation, the sensing layers  108  of the first exemplary embodiment sense ( FIG. 2 ) the position of fingers  120  and the thumb  122  applied in a first position by the user. The fingers  120  sensed may be a single finger or up to four fingers. As the fingers  120  and thumb  122  move on the surface of the knob  102 , a gain  502  is provided as illustrated in  FIG. 5 . When the fingers  124  and thumb  126  are positioned on the knob  102  in a second position as illustrated in  FIG. 6 , a gain  504  is provided. 
     Referring to  FIG. 7 , a second exemplary embodiment includes a knob  702  rotationally mounted to an electronic device  704  by an axial rod  706 . The axial rod  706  may pass through a optional housing  708  in which the electronic device  704  may be disposed. The knob  702  and axial rod  706  may be comprised of any rigid material, for example, plastic, rubber, or metal. When the knob  702 , and the axial rod  706  securely mounted thereto, are rotated by a user turning the knob  702 , a rotation sensing device (not shown) such as a rheostat within the electronic device  104  senses this rotation and converts it to an electronic signal indicative of the amount of rotation. In accordance with the preferred embodiments, touch sensing layers  710  are disposed on the outer surface of the rigid material of knob  702  for detecting the placement of fingers on the knob  702  in a similar fashion to the first embodiment described above. When fingers and thumbs are positioned in a first position on the knob  702  a first gain is provided to the rotation and when the fingers and thumbs are positioned in a second position on the knob  702 , a second gain is provided. 
     Referring to  FIGS. 8 and 9 , a third exemplary embodiment includes the knob  802  that has a shape similar to the gain curve  902  ( FIG. 9 ) that it provides. 
     In a fourth embodiment, a thin layer comprising a texture, for example, a semi-flexible layer containing electro-rheological or magneto-rheological fluid, that varies in proportion to the amount of pressure results in a variable degree of ease in which the fingers moves across the surface. This fluid changes in viscosity proportional to electric or magnetic field. So as more pressure is applied, the gain changes, and a corresponding electro or magnetic field is applied to the fluid and the viscosity increases, making it harder to move across the surface. This increase or decrease in texture and ease of finger movement is sensed by the finger&#39;s touch. This textured layer preferably comprises the protective layer  112 . 
     While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, 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 an exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.