Abstract:
Embodiments related to dual mode rotatable input devices that permit both resistive and non-resistive rotation are disclosed. One embodiment comprises a stationary hub, a rotatable member rotatable around the stationary hub, and a resistive rotation mechanism forming an interface between the stationary hub and the rotatable member. The resistive rotation mechanism comprises a resistive surface and a movable interface member configured to selectively contact the resistive surface, wherein the resistive surface and the movable interface member move relative to one another with rotation of the rotatable member. The resistive mechanism further comprises a biasing mechanism that urges the movable interface member into engagement with the resistive surface when a rotational velocity of the rotatable member is below a threshold velocity, and allows separation of the interface member and the resistive surface when the rotational velocity of the rotatable member is above the threshold velocity.

Description:
BACKGROUND 
     Many electronic devices utilize rotatable inputs to allow a user to make an input by rotating a dial, wheel, or the like. As one example, computer mice often include scroll wheels rotatable by a user to scroll a list, a document, or other object displayed on a graphical user interface of a computing device. 
     Various rotatable input devices include mechanical features that facilitate fine-scale input control. For example, some scroll wheels may include indexing features that cause the scroll wheels to rotate in a stepped manner, while other scroll wheels may utilize frictional resistance to allow fine control over a continuous range of positions. However, in either case, such fine control mechanisms may impede rapid scrolling through large lists. 
     SUMMARY 
     Accordingly, various embodiments related to dual mode rotatable input devices are disclosed herein that permit both resistive and non-resistive rotation. For example, one disclosed embodiment provides a rotatable input device for an electronic device, wherein the input device comprises a stationary hub, a rotatable member configured to be rotatable around the stationary hub by a user, and a resistive rotation mechanism forming an interface between the stationary hub and the rotatable member. The resistive rotation mechanism comprises a resistive surface and a movable interface member configured to selectively contact the resistive surface, wherein the resistive surface and the movable interface member are configured to move relative to one another with rotation of the rotatable member. The resistive mechanism further comprises a biasing mechanism configured to urge the movable interface member into engagement with the resistive surface when a rotational velocity of the rotatable member is below a threshold velocity, and to allow separation of the interface member and the resistive surface when the rotational velocity of the rotatable member is above the threshold velocity. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a view of an embodiment of a computer mouse with a rotatable input device in the form of a scroll wheel. 
         FIG. 2  shows a view of an embodiment of a dual-mode scroll wheel for a computer mouse, and illustrates a first mode of the scroll wheel. 
         FIG. 3  illustrates a second mode of the scroll wheel of  FIG. 2 . 
         FIG. 4  shows an embodiment of a dual-mode scroll wheel having bearing channels oriented out of a plane of the scroll wheel. 
         FIG. 5  shows an embodiment of a dual-mode scroll wheel having bearing channels oriented in a plane of the scroll wheel. 
         FIG. 6  shows an embodiment of a dual-mode scroll wheel having one magnet corresponding to two detents. 
         FIG. 7  shows an embodiment of a dual-mode scroll wheel utilizing a plurality of springs as a biasing mechanism. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments of rotatable input devices are disclosed herein that are selectively changeable between resistive and non-resistive rotation modes to allow both fine control at low rotation velocities and rapid movement through a large range of items at high rotation velocities. For example,  FIG. 1  shows an embodiment of a computer mouse  100  having a scroll wheel  102  that may be used to scroll through a list of items on a graphical user interface of a computing device. 
       FIG. 2  shows a sectional view of the scroll wheel  102  when at rest or being rotated at a low rotational velocity, and  FIG. 3  shows a sectional view of the scroll wheel  102  when rotated at a higher rotational velocity. The scroll wheel  102  comprises a stationary hub  200 , a rotatable member  202  (i.e. the outer portion of the scroll wheel  102  that is manipulated by a user), and a resistive rotation mechanism, indicated generally at  206 , that forms an interface between the stationary hub  200  and the rotatable member  202 . While disclosed herein in the context of a scroll wheel for a mouse, it will be understood that the rotatable input device of  FIGS. 2-3  may be used with any other suitable rotatable control, and in any suitable use environment. It will be understood that motion of the scroll wheel  102  may be tracked via optical encoding, or via any other suitable method. Such motion tracking mechanisms are omitted from these figures for the purposes of clarity. 
     The depicted resistive rotation mechanism  206  comprises an indexed surface  210 , and one or more moveable interface members  212  configured to selectively interface with the indexed surface  210 , depending upon a velocity at which the rotatable member  202  is rotated by a user. The resistive rotation mechanism  206  also comprises a biasing mechanism  214  configured to urge the moveable interface members  212  into engagement with the indexed surface  210  when the rotational velocity of the rotatable member  202  is below a threshold velocity, and to separate the interface members  212  and the indexed surface  210  when the rotational velocity of the rotatable member  202  is above the threshold velocity. In this manner, the rotatable member  202  automatically switches between resistive and non-resistive rotation depending upon how fast a user rotates the scroll wheel  102 . It will be understood that other embodiments may utilize a non-indexed resistive surface without such detents, but that otherwise operates in a like manner. Further, it will be understood that the term “resistive rotation” as used herein denotes any “fine control” rotation mode that has additional friction or other resistance (indexed or non-indexed) compared to a lower-resistance mode of rotatable input device, and the term “non-resistive rotation” denotes any rotation mode that has lower friction or other resistance compared to a fine control mode. 
     The use of scroll wheel  102  in a computer mouse provides a simple and effective dual mode (resistive/non-resistive) scroll wheel for a computer mouse that switches between the modes without any input from a user other than ordinary manipulation of the scroll wheel that occurs during normal use. This is in contrast to other dual mode scroll wheels, which have a button or other control selectable by a user to switch between resistive and non-resistive rotation, for example, via a motor or mechanical coupling that engages or disengages a resistance mechanism. 
     A rotatable input device according to the present disclosure may utilize any suitable structure or structures to add resistance to lower velocity operation. For example, in the embodiment depicted in  FIGS. 2-3 , the indexed surface  210  comprises a plurality of detents  220  formed on an outer radial perimeter of the stationary hub  200 , and the movable interface member comprises a plurality of bearings  222  each disposed within a corresponding internal space  224  formed in the rotatable member  202  that has an opening facing the indexed surface  210 . The internal space  224  may be referred to herein as a “bearing holder” in the context of specific embodiments that utilize bearings as a movable interface member. 
     Further, the biasing mechanism  214  comprises a magnet  226  disposed within the stationary hub at a location adjacent to the detents. When the scroll wheel  102  is rotated at a rotational velocity less than a threshold velocity, the attraction between the magnet  226  and each bearing  222  is sufficient to pull the bearing into the detents  220  as each bearing  222  is moved past the detents  220 . Therefore, at these rotational velocities, the movement of each bearing  222  into and out of the detents  220  gives the rotation of the scroll wheel  102  an indexed feel that allows precise control for fine-scale input control. 
     On the other hand, as illustrated in  FIG. 3 , where the rotational velocity of the scroll wheel  102  is above the threshold velocity, the attractive force of the magnet  226  is insufficient to overcome the centripetal force exerted by the bearings  222  against the “bottom” surfaces in internal spaces  224  (i.e. the surfaces of the internal spaces farthest from the stationary hub  200 ). Therefore, when operated at these rotational velocities, the bearings  222  do not engage with the detents, allowing the scroll wheel  102  to freely spin without indexed movement. In this manner, the scroll wheel  102  may be “flicked” at a high rotational velocity to facilitate scrolling through large documents via unindexed, unimpeded motion of the scroll wheel. 
     The various dimensions of the stationary hub  200 , rotatable member  202 , bearings  222 , internal spaces  224 , and other parts of the scroll wheel  102  may have any suitable values. For example, the mass of each bearing  222  and the depth of the bearing holders  224  may be selected to tailor the centripetal force threshold between resistive and non-resistive rotation to fall at a desired rotational velocity. For example, in one specific embodiment configured to enable non-resistive rotation of the scroll wheel at 1000 rpm, each bearing may have a mass of approximately 50 mg and each bearing holder  224  may have a depth of between approximately 1.5-3 mm. 
     Likewise, a number of and spacing of detents compared to a number of and spacing of bearings may be selected to tailor the spacing between indices to a desired value in light of an amount of space available on the rotatable member  202  and/or the stationary hub  200 . For example, where it is desired to have relatively closely spaced indices, there may be insufficient space to increase a number of bearings within the rotatable member  202 . Therefore, as shown in  FIGS. 2-3  two or more detents  220  may be provided on the indexed surface  210  so that each bearing encounters multiple detents. In this manner, a radial spacing between indices may be increased without increasing a number of bearings within the rotatable member  202 . As a more detailed example, if it is desired to have  20  degrees between indices, a scroll wheel may be provided with eighteen bearings and one detent, nine bearings and two detents, six bearing and three detents, etc. While the depicted movable interface member comprises one or more bearings, it will be understood that any other suitable structure may be used as moveable interface member, including but not limited to pins, rollers, etc. 
     The level of resistance encountered at each index may be tailored by selection of detent depth and profile, as well as magnet strength. For example, relatively high-resistance indices may be formed via the use of a relatively stronger magnet and/or relatively deeper detents, while relatively lower resistance indices may be formed via the use of a relatively weaker magnet and/or relatively shallower detents. 
     In some embodiments, the surfaces within each bearing holder  224  may comprise a relatively soft surface configured to reduce noise from the movement of bearings  222  within the bearing holders  224  during use. For example, a two-shot injection molding process may be used to form rotatable member  202 , stationary hub  200 , etc. from a hard plastic, and to form a softer plastic or elastomeric coating within the bearing holders  224  and/or over indexed surface  210 . In one specific embodiment, the rotatable member is formed from an acetyl plastic with an approximately 1 mm thick thermoplastic elastomeric coating formed within the bearing holders  224 . 
       FIGS. 4 and 5  show sectional views of two embodiments of scroll wheels taken along a direction normal to a rotational axis of the scroll wheels. First referring to  FIG. 4 , the bearing holders  224  are arranged at an angle relative to a plane in which the rotatable member  202  rotates. This may help to prevent bearings from rolling out of the bearing holders  224  during device construction. Alternatively, as shown in  FIG. 5 , the bearing holders  524  may be arranged parallel to the plane in which the rotatable member  502  rotates on stationary hub  500 . 
     The embodiment of  FIGS. 2 and 3  show the use of a single magnet disposed beneath two closely-spaced detents such that a single pole of the magnets provides the biasing force associated with both detents. In other embodiments, one magnet may be provided for each detent. In yet other embodiments, both poles of a single magnet may be utilized to provide biasing force for two detents.  FIG. 6  shows an embodiment of a scroll wheel  600  in which a single U-shaped magnet  602  is used to provide biasing force for two detents  604 ,  606 . A first pole  603  of the U-shaped magnet  602  is located adjacent to a first detent  604 , and a second pole  605  of the U-shaped magnet is located adjacent to a second detent  606 . By utilizing both poles of a magnet in this manner, a single magnet can be used to efficiently provide biasing force to two detents. This may allow space within the stationary hub to be used efficiently. 
       FIG. 7  shows another embodiment of a rotatable input device  700  according to the present disclosure. Instead of utilizing one or more magnets to provide biasing force, input device  700  utilizes a spring  702  disposed within each internal space  704  to bias movable interface members in the form of bearings  706  toward a resistive surface  708 . While coil sprigs are shown as springs  702 , it will be understood that any other suitable type of spring may be used, including but not limited to leaf springs, etc. 
     In the depicted embodiments, the movable interface member is shown as being incorporated into a rotatable member of a scroll wheel, and the resistive surface against which the interface member is biased is shown as being disposed on an outer surface of a stationary hub. However, in other embodiments, a movable indexed surface may be located on a rotatable portion of a scroll wheel, and the interface member may be located on a stationary hub. Further, in other embodiments, both the resistive surface and interface member may be located on structures external to the scroll wheel that are, for example, connected to the rotatable member of the scroll wheel via a drive shaft, suitable gearing, etc. In yet other embodiments, the movable interface member may comprise one or more pins disposed within the rotatable member that are configured to strike elastomeric ridges that extend from the stationary hub toward the rotatable member. 
     The depicted embodiments allow a user to select between rotation modes simply by changing a rotational velocity of a rotatable input member. The disclosed rotatable input devices do not utilize complex assembly procedures, and operate entirely on mechanical principles. Therefore, the use of the disclosed rotatable input devices with computer mice does not affect the optical encoder or electronics of a mouse, thereby facilitating use of the disclosed input devices in existing mouse designs. It should be understood that the dual-mode rotation configurations and/or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be considered in a limiting sense, because numerous variations are possible. The subject matter of the present disclosure includes all novel and non-obvious combinations and subcombinations of the various processes, systems and configurations, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof.