News Column

Researchers Submit Patent Application, "Touch Screen, Portable Electronic Device, and Method of Operating a Touch Screen", for Approval

July 16, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors Holmberg, Per (Lund, SE); Kulle, Tomas (Hjarup, SE); Rosqvist, Bjorn (Lund, SE); Klinghult, Gunnar (Lund, SE); Johansson, Allan (Lund, SE); Knutsson, Lars (Sjobo, SE); Anton, Georgeta (Dalby, SE); Aberg, Peter (Vinsolv, SE), filed on December 20, 2012, was made available online on July 3, 2014.

The patent's assignee is Sony Ericsson Mobile Communications Ab.

News editors obtained the following quote from the background information supplied by the inventors: "Portable electronic devices provide functionalities which continue to be enhanced. With increasing processing capabilities and functionalities provided in the portable electronic device, it is increasingly challenging to provide input interfaces, for example in the form of touch screens, which allow the variety of functionalities and functions to be controlled in a direct and intuitive manner. Touch screens which sense touch action of a user enhance the way in which the user can interact with a portable electronic device. For example, touch screens are known which allow to determine a lateral position of a touch action or of a plurality of touch actions. This is referred to as multi-touch scenarios in which several fingers are used to simultaneously actuate different regions of the touch screen. For example it is often used to track the movement of a user's finger across a window on top of the touch screen. Based on the sensed lateral position of the touch action or the plurality of touch actions, a processor is configured to control at least one function of the portable electronic device.

"One approach to further enhance the operation of touch screens is to derive information on a force of the touch action. For example, such information may be derived from the size of the area at which a user contacts a window of the touch screen. This is because the size of this area typically provides information on how the user places his or her finger on the window. Typically, if the user places the finger with a stronger force against the window, the area over which the touch action is detected will increase. While this approach does not require a separate sensor by deriving additional information from the size of the area in which the window is touched, it has shortcomings. It may be challenging to discriminate between users pushing against the window lightly with an index finger having large dimensions and users pushing strongly against the window with an index finger having small dimensions. Other approaches of determining the force of a touch action include providing separate sensor systems for determining the force. Also such systems have shortcomings. For example, the requirement of providing additional parts forming the additional sensor system for detecting the force of a touch action can result in increased space requirements which can make the portable electronic device larger in an undesired manner. Also, because additional parts have to be included in the portable electronic device, costs can increase and mean time between failure may decrease."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "Accordingly, a need exists to provide advanced touch screens, advanced portable electronic devices, and advanced methods of operating touch screens which allow for additional information on the user's actuation on the touch panel to be derived.

"This need is met by the independent claims. The dependent claims define embodiments.

"According to an aspect, a touch screen responsive to a touch action and arranged in a housing having a bottom surface is provided. The touch screen comprises a display, a sensor system, and a processor. The display for displaying through a front surface of the display is mounted inside the housing and further comprises a back surface being offset by a gap from the bottom surface of the housing in a direction perpendicular to the bottom surface. The sensor system is interposed between the back surface and the bottom surface and comprises a first electrode assembly and a second electrode assembly. The first electrode assembly comprises at least one electrode and the second electrode assembly comprises at least one electrode. The sensor system is configured to sense capacitance between the first electrode assembly and the second electrode assembly. The processor is configured to determine, based on the sensed capacitance, a force resulting from the touch action.

"The processor being configured to determine the force resulting from the touch action may do so by, for example, using a look-up table linking sensed capacitance with force. Also, it may be possible that the processor calculates the force using a predefined mathematical formula using the sensed capacitance as an input. Also a combination of such techniques may be possible. The determined force may comprise a magnitude and/or an orientation of the force. By accordingly configuring the first and second electrode assemblies, it may be possible to derive both magnitude and orientation of the force from the sensed capacitance.

"For example, the housing may be a recess in a main body of a portable electronic device which employs the touch screen. If the touch screen is arranged in the housing forming the recess, it may be safe against undesired external influences, such as dust, fine particles, shock or liquids. In particular, edges of the touch screen, for example of a window arranged offset from the front surface, may be flush with edges of the housing such that foreign matter may be prevented from entering the inside area of the housing where the touch screen is arranged. The window may form a top surface of the touch screen. The front surface of the display may be arranged underneath the window, i.e., underneath the top surface, at a side of the display opposite to the side at which the back surface of the display is arranged. Provisioning of a gap between the back surface of the display and the bottom of the touch screen may be helpful in order to avoid unintended effects of degraded display quality when the user actuates the touch screen by a touch action. When the display is displaced due to the touch action, it may be desired to avoid contact between the back surface of the display and any other parts within the housing, in particular the bottom surface. Typical dimensions of the gap into which the sensor system is interposed, i.e., between the back surface of the display and the bottom surface of the housing, may be 0.3 mm.

"Then, by interposing the sensor system between the back surface and the bottom surface, i.e. within the gap, already existing space within the housing may be favourably used to sense the capacity. Namely, when the touch action displaces the back surface of the display, the capacity between the first electrode assembly and the second electrode assembly may be altered because the top and bottom electrodes forming the electrode assemblies are brought closer together. The displacement may depend on the force of the touch action. Therefore, it may be possible to use this altered capacitance due to displacement in order to determine the force of the touch action.

"The at least one electrode of the first electrode assembly may be integrally formed by the back surface of the display or may be attached to the back surface of the display. Likewise, the at least one electrode of the second electrode assembly may be integrally formed by the bottom surface of the housing or may be attached to the bottom surface of the housing.

"By integrally forming the first and/or second electrode assemblies by the back surface and the bottom surface, respectively, the effect of a reduced number of parts necessary to built the sensor system may be achieved. This may reduce costs in procurement and assembly, and may increase the mean time between failure. Yet, if at least one of the electrodes of the first electrode assembly or at least one of the electrodes of the second electrode assembly is attached to the back surface of the display or the bottom surface of a housing, respectively, this may have the effect of increased flexibility of the arrangement of the electrodes. For example, a plurality of electrodes in different patterns may be provided if it is not necessary to rely on already existent other parts. Still, because the electrodes are interposed into the anyway existing gap, no additional space may be required. This may be desirable for applications targeting at portable electronic devices.

"The processor may be further configured to determine the force based on differences of the sensed capacitance to a reference capacitance. Sensing differences to a reference capacitance, i.e., an offset capacitance, may have the effect of reduced error when determining the force. For example, manufacture tolerances of the dimensions between different touch screens of different portable devices or between different parts of the first and second electrode assembly or between different regions of individual electrodes may be compensated when determining the force by determining an offset of the sensed capacitance.

"The sensor system may be further configured to sense capacitance spatially resolved and the processor may be configured to determine a lateral position of the touch action based on the spatially resolved sensed capacitance. By determining the lateral position of the touch action, further information may be available which can be used for controlling of functions of, e.g., a portable electronic device which comprises the touch screen. Different actions may be triggered depending on the lateral position and/or the force. In particular, it may be possible to provide interaction between a further sensor system being configured to determine a lateral position of the touch action, e.g., with larger lateral resolution. Different control schemes for functions of, e.g., a portable electronic device are conceivable which rely on the combined knowledge of position and force of a touch action or multi-touch action.

"The display may be a liquid crystal display having a back reflector forming the back surface. A typical liquid crystal display (LCD) may consist of a polarizer, a color filter, a liquid crystal, a thin film transistor, a backlight, and a back reflector. The back reflector may have a surface which is optimized to reflect light emitted by the backlight towards the back surface into the direction of the front surface. However, it may also be possible that the back reflector forming the back surface has electrical properties which allow that the at least one electrode of the first electrode assembly is integrally formed by the back reflector. For example, the back reflector may have electrical characteristics, e.g., conductivity, of a metal. It may also be possible that the display is a organic light emitting diode (OLED) type display or any other type of display.

"Moreover, at least one of the bottom surface of the housing, the back surface of the display, the first electrode assembly, or the second electrode assembly may be made out of a metal selected from the group comprising: conductive material, copper foil, electrolyte copper, metal. Such materials may have the effect of electronic properties which are suited for serving as electrodes in capacitance sensing by the sensor system. For example, the usage of such materials may have the effects of increased reference capacitance, offset capacitance, and increased signal-to-noise ratio of the sensed capacitance. As a result, the force may be more accurately determined.

"The touch screen may comprise a further sensor system arranged offset to the front surface of the display in a direction perpendicular to the front surface, wherein the further sensor system is configured to sense a further signal. The touch screen may further comprise a further processor being configured to determine, based on the further signal, a lateral position of the touch action with a further lateral spatial resolution. By providing a further sensor system, e.g., in the form of a touch panel, which is arranged offset to the front surface of the display, the further sensor system may be arranged closer to a window where the touch action occurs, i.e., in the direction perpendicular to the front surface and orientated away from the back surface. In particular, if the further system is a capacitive sensor system, the further signal may have an increased signal-to-noise ratio. The lateral position of the touch action which is sensed by the further sensor system may therefore be accurately determined. Noise and background influences may be reduced. For example, it may be possible to optimize the sensor system for accurate force sensing and the further sensor system for accurate lateral position sensing.

"In particular, a lateral spatial resolution of the sensor system may be smaller than the further lateral spatial resolution of the further sensor system. Information on the lateral position of the touch action may therefore be derived primarily from the further signal rather than from the capacitance sensed by the sensor system. The sensor system may be primarily employed to determine the force of the touch action while the further sensor system may be primarily employed to determine the position of the touch action.

"Yet, the sensor system may be configured to individually sense capacitance between the at least one electrode of the first and second electrode assemblies and the processor may be further configured to determine the force in a spatially resolved manner based on the individually sensed capacitance. For example, if a plurality of electrodes is provided, by individually sensing the capacitance at each electrode, together with information on the arrangement of the electrodes, a spatial resolution may be obtained for the signal of the sensor system. Using electrodes having a large lateral spatial extent may have the effect of an increased signal-to-noise ratio, i.e., an increased accuracy, when determining the force--while only a comparably low spatial resolution may be obtained. Then, the determined force of different constituent touch actions of a multi-touch action may be linked with the respective high-resolution lateral positions obtained from a further sensor system.

"For example, at least one of the first electrode assembly or the second electrode assembly may comprise at least four electrodes which may be arranged in a lateral pattern. By provisioning a plurality of electrodes and arranging the plurality of the electrodes in a predefined lateral pattern, spatial resolution in sensing the capacitance may be obtained. This may allow for further possibilities in the control of, e.g., a portable electronic device which is coupled to the touch screen.

"The at least one electrodes of at least one of the first electrode assembly and the second electrode assembly may have an outer circumference substantially congruent with the outer edges of the back surface or the bottom surface, respectively. In such a scenario, the force of the touch action may be sensed even at positions close to the edges of the touch screen, i.e., across a wide area. This may have the effect of the user being able to employ the force of the touch action as an input means at the edges of the touch screen area.

"To this respect, the first electrode assembly may cover an area substantially equal to the area covered by the back surface and/or the second electrode assembly may cover an area substantially equal to the area covered by the bottom surface. In such a case, it may be possible to sense the force of the touch action at any position across the display.

"The display may comprise electronic circuitry being positioned offset from the back surface. The at least one electrode comprised in the first electrode assembly may be coupled to the electronic circuitry and the sensor system may address the at least one electrode via the electronic circuitry to sense capacitance. Typically, a display, e.g. a LCD or organic light emitting diode (OLED) type display, already may comprise electronic circuitry which is used for operation. If such electronic circuitry is positioned offset from the back surface, this may have the effect of allowing, for example, additional interfaces being provisioned in order to couple the electronic circuitry with the at least one electrode of the first electrode assembly being positioned close to the back surface of the display. By this, the sensor system may address the at least one electrode via the electronic circuitry to sense the capacity. In such a scenario, the amount of additional circuitry required in order to operate the sensor system may be reduced. This may reduce costs and potential for failure.

"The first electrode assembly may comprise a plurality of top electrodes and the second electrode assembly may comprise a single bottom electrode, wherein the bottom electrode may be a ground electrode. For example, the bottom electrode may be integrally formed by the bottom surface of the housing being a mold steel frame. By provisioning a single ground electrode and a plurality of top electrodes, spatial resolution of the sensed force of the touch action may be achieved while reducing the number of parts necessary to build the sensor system. Capacity may be measured against one ground electrode by the different top electrodes. Also by employing the steel frame of the housing as a common ground electrode, already existing parts of the touch screen may be employed.

"According to a further aspect, a portable electronic device is provided. The portable electronic device comprises a main body comprising a housing having a bottom surface, the housing forming a recess in the main body. The portable electronic device further comprises a touch screen responsive to a touch action and being arranged in the housing. The touch screen comprises a display and a sensor system and a processor. The display for displaying through a front surface of the display is mounted inside the housing and further comprises a back surface being offset by a gap from the bottom surface of the housing in a direction perpendicular to the bottom surface. The sensor system is interposed between the back surface and the bottom surface and the sensor system comprises a first electrode assembly comprising at least one electrode and a second electrode assembly comprising at least one electrode. The sensor system is configured to sense capacitance between the first electrode assembly and the second electrode assembly and the processor is configured to determine, based on the sensed capacitance, a force resulting from the touch action. The processor is further configured to control at least one function on the portable electronic device.

"For example, the edges of the touch screen may be substantially flush with the edges of the recess formed by the housing in the main body. For example, the touch screen may comprise a window forming a top surface on which the touch action occurs. Then the edges of the window may be substantially flush with the edges of the recess. This may prevent dust, small particles, liquids etc. from entering the housing and thus protect the display.

"The touch screen may be configured according to the touch screen of the further aspect of the present invention.

"For such a portable electronic device effects may be obtained which are comparable to the effects obtained for the touch screen according to the further aspect of the present application.

"According to a further aspect, a method of operating a touch screen comprising a display and being arranged in a housing is provided. The method comprises displaying through a front surface of the display, sensing a capacitance between a first electrode assembly and a second electrode assembly of a sensor system, the sensor system being interposed between a bottom surface of the housing and a back surface of the display opposing the front surface of the display. The method further comprises determining, based on the sensing of the capacitance, a force resulting from the touch action.

"For such a method, effects may be obtained, which are comparable to the effects obtained for the touch screen of the further aspect of the present application and/or the portable electronic device of the further aspect of the present application.

"It should be understood that the features mentioned above and features yet to be explained below can be used not only in a respective combinations as indicated, but also in other combinations or in isolation, without departing from the scope of the present invention. Features of the above-mentioned aspects and embodiments may be combined with each other in other embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

"The foregoing and additional features and effects of the application will become apparent from the following detailed description when read in conjunction with the accompanying drawings, in which like reference numerals refer to like elements.

"FIG. 1 is a top view of a portable electronic device.

"FIG. 2 is a cross-sectional view of the portable electronic device along the line labelled X-X in FIG. 1 according to an embodiment.

"FIG. 3 is a cross-sectional view of the portable electronic device along the line labelled X-X in FIG. 1 according to a further embodiment.

"FIG. 4 is a top-view of a first electrode assembly according to an embodiment.

"FIG. 5 is a top-view of a first electrode assembly according to a further embodiment.

"FIG. 6 is a top-view of a first electrode assembly according to a further embodiment.

"FIG. 7 is a top-view of a first electrode assembly according to a further embodiment.

"FIG. 8 is a schematic illustration of the portable electronic device of FIG. 1.

"FIG. 9 is a flowchart of a method of operating a touch screen.

"FIG. 10 shows a dependency of a magnitude of a force on a sensed capacitance."

For additional information on this patent application, see: Holmberg, Per; Kulle, Tomas; Rosqvist, Bjorn; Klinghult, Gunnar; Johansson, Allan; Knutsson, Lars; Anton, Georgeta; Aberg, Peter. Touch Screen, Portable Electronic Device, and Method of Operating a Touch Screen. Filed December 20, 2012 and posted July 3, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=5552&p=112&f=G&l=50&d=PG01&S1=20140626.PD.&OS=PD/20140626&RS=PD/20140626

Keywords for this news article include: Electronics, Light-emitting Diode, Sony Ericsson Mobile Communications Ab.

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


For more stories covering the world of technology, please see HispanicBusiness' Tech Channel



Source: Electronics Newsweekly


Story Tools






HispanicBusiness.com Facebook Linkedin Twitter RSS Feed Email Alerts & Newsletters