Apple is considering over forms of input for its iPod/iPhone range. This pat application recently released describes using the rear surface of an iPod/iPhone as the input surface. Touching this surface would change the UI on the front surface of the device. The touch-sensitive surface would be configured that differences in pressure could be used to indicate a click (“no need to lift a finger”). Additionally, the rear surface could have etched markings indicating special control areas (e.g. an etched scrollwheel to aid scrolling). Perhaps this work indicates that Apple thinks that the front surface touch screen as seen in the iPhone has some serious drawbacks (screen smudging, scratching etc). This represents further evidence that Apple will be updating the iPod line to include more sophisticated touch-senstive surfaces.

Title: Back-Side Interface for Hand-Held Devices
Inventors: Elias; John G.; (Townsend, DE)
Assignee Name: Apple Computer, Inc.
Serial No.: 620424
Series Code: 11
Filed: January 5, 2007
Apple describes in a new Patent application an electronic device that uses separate surfaces for input and output. One of the surfaces (e.g., the bottom) includes a force-sensitive touch-surface through which a user provides input (e.g., cursor manipulation and control element selection). On a second surface (e.g., the top), a display element is used to present information appropriate to the device’s function (e.g., video information), one or more control elements and a cursor. The cursor is controlled through manipulation of the back-side touch-surface. The cursor identifies where on the back-side touch-surface the user’s finger has made contact. When the cursor is positioned over the desired control element, the user selects or activates the function associated with the control element by applying pressure to the force-sensitive touch-surface with their finger. Accordingly, the electronic device may be operated with a single hand, wherein cursor movement and control element selection may be accomplished without lifting one’s finger.

An increasingly popular form of electronic device is the hand-held multi-media device. Illustrative devices of this type include palm or hand-held personal computers, tablet computer systems, mobile telephones, personal digital assistants, portable video players and portable audio players. One specific example of such a device is the video iPod.RTM. from Apple Computer. (IPOD is a registered trademark of Apple Computer, Inc.) In this class of device the display screen, typically a liquid crystal display (“LCD”), is often to small to make effective use of finger based touch input. Although a touch-screen interface could be embedded in or overlaid on the display, the use of even a single finger for input may occlude a significant portion of the display or cover more than a single operational control element. While this problem could be mitigated by limiting the touch area to a portion of the display screen (e.g., the display edges where horizontal or vertical motion could emulate slider controls), a single finger could still cover a substantial amount of the useful display area. In addition, display smudging is a problem as with all finger sensitive touch-screen interfaces. While stylus based touch-screens may be used to partially reduce the occluding problem and eliminate smudging, they suffer a large disadvantage compared to finger based touch-screen systems in that they require the storage and removal of a stylus. In addition, for small hand-held devices a stylus input requires the use of two hands: one to hold the device and one to hold and manipulate the stylus.

In yet another embodiment in accordance with the invention, device 500 displays alpha soft keys 505 on display element 215 on front surface 210. By selecting various keys 505, the user may enter character strings (e.g., string 510). As before, the user positions cursor 515 through movement of their fingers across the device’s back-side force-sensitive touch-surface; button selection is made through the application of pressure to the back-side touch-surface. As shown, device 500 displays alpha buttons 505 transparently so that the user may continue to view information that may be displayed “beneath” them. Of course, buttons 505 may be opaque.

In still another embodiment, a multi-media hand-held device having a back-side force-sensitive touch-surface may utilize two or more of the interfaces described above. For example, in a first mode (e.g., a music playback mode), the click-wheel interface described above with respect to FIGS. 3A and 3B could be employed (with or without backside surface etching). In another mode (e.g., a telephone mode), the interface described above with respect to FIG. 4 could be implemented. In still another mode (e.g., text input, electronic mail or instant messaging modes) the alpha interface described in connection with FIG. 5 may be used. Other interfaces will be apparent to one of ordinary skill in the art having the benefit of this disclosure.

In some embodiments, the display of control elements and/or a menu may be triggered by a specific user action. For example, by the user holding their finger on back-side touch-surface 225 within the region defined by an etched control element (e.g., click-wheel 305) for a specified period of time (e.g., one second). Another user action to trigger activation of a mode-appropriate user interface would be to simply hold one or more fingers against the back-side force-sensitive touch-surface for a specified period of time and with at least a minimum specified force (e.g., a “light” grip or poke).

Alternatively, a change in device 200′s operational state may cause the same result. For instance, appropriate control element or menu may be displayed when device 200 transitions from a first state to a second state. Illustrative operational states include, but are not limited to–on, off, locked, phone mode, video play mode, audio play mode, calendar mode, email mode, address book mode and image capture mode. Thus, a single user action may have cause different control elements to be displayed (or no control elements at all), depending on the device’s current operational state.