Touch screen with soft key enabling electromagnetic resonance input

A touch screen and a method for controlling the touch screen are provided. The touch screen includes a user interface including a display area and at least one soft key; a touch sensor unit disposed under the display area and the at least one soft key of the user interface, for sensing a touch on the display area or the at least one soft key; a display unit disposed under the touch sensor unit, for outputting a display screen; a first electromagnetic sensor unit disposed under the display unit, for sensing an electromagnetic field incident on the display area; and a second electromagnetic sensor unit physically separated from the first electromagnetic sensor unit, for sensing at least one electromagnetic field incident on the at least one soft key.

PRIORITY

This application claims priority under 35 U.S.C. §119(a) to a Korean Patent Application filed in the Korean Intellectual Property Office on Jul. 12, 2011 and assigned Serial No. 10-2011-0069165, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a touch screen with a soft key and more particularly, to a touch screen with a soft key enabling electromagnetic resonance input.

2. Description of the Related Art

Along with the recent rapid growth of the market for smart phones and touch screens, extensive research has been conducted for these products. A user can input a specific command to a smart phone or other device having a touch screen by selecting a specific position or icon on the display of the smart phone or touch screen with a user's body part or with an ElectroMagnetic Resonance (EMR) pen.

This input scheme can be implemented through a capacitive touch screen. A capacitive touch screen generally includes transparent electrodes and condensers. As the user touches the touch screen with a body part, the touch may be sensed based on the resulting changed capacity of a condenser.

However, since a capacitive touch screen requires a user's touch, this input scheme may be inconvenient for a user and providing accurate input may be difficult. Due to this inconvenience, EMR input has recently become an active study area.

An EMR type input on a touch screen involves controlling generation of electromagnetic waves by applying a voltage to a loop coil disposed on a Printed Circuit Board (PCB) and controlling absorption of the electromagnetic waves into an EMR pen. The EMR pen may include a condenser and a loop and emit the absorbed electromagnetic waves in a specific frequency.

The electromagnetic waves emitted from the EMR pen may be absorbed again into the loop coil of the PCB so that a position near to the EMR pen on the touch screen can be determined based on the absorbed electromagnetic waves.

Meanwhile, a pen may operate in an ElectroMagnetic (EM) fashion as well in the EMR fashion. An EM pen may include a coil for electromagnetic output and an internal power supply for applying a voltage to the coil.

FIGS. 1A, 1B and 1Care conceptual views of a conventional EMR scheme.

FIG. 1Ais a diagram illustrating a communication device100with an electromagnetic sensing circuit operating in a conventional EMR scheme.

Referring toFIG. 1A, the communication device100may include a display110and soft keys120.

The display110displays information to a user. The display110may operate in an EMR scheme and/or a capacitive scheme.

The soft keys120are a user interface provided separately from the display110, which enables the user to intuitively perform basic functions such as back, cancel, menu display control, etc. Conventionally, the soft keys120operate only in the capacitive scheme due to limitations on accommodation of capacitive sensors and electromagnetic sensors under transparent electrodes. Conventional soft keys do not have built-in electromagnetic sensors.

FIG. 1Bis a diagram illustrating a plurality of loops arranged in the display ofFIG. 1.

Referring toFIG. 1B, a plurality of loops131to134may be arranged such that the loops overlap with each other. When the user's an EMR pen is moved close to a specific position on the display110, the loops131to134may sense an electromagnetic field from the EMR pen.

FIG. 1Cis a graph illustrating induced voltage with respect to the loops of the display ofFIG. 1B.

Referring toFIG. 1C, each of the loops131to134may output current induced by the sensed electromagnetic field. A loop closer to the EMR pen will sense an electromagnetic wave with a larger amplitude than loops further away from the EMR pen, and each loop will emit an induced voltage corresponding to the sensed electromagnetic wave. Therefore, induced voltages with different magnitudes may be output as illustrated inFIG. 1C.

A microprocessor built in the communication device100may determine a peak by interpolating the magnitudes of the output induced voltages and thus may determine a user-input position on the display.

As stated before, since only the capacitive scheme is used for the soft keys120, the user must input commands to the soft keys120by touching the soft keys120with a body part. Moreover, when the user's body part touches a soft key120, while using an EMR pen, an unintended input such as execution of a back operation through a corresponding soft key may occur. Accordingly, there exists a need for developing a structure for disabling user input via a touch on the soft keys120, when a user uses an EMR pen.

SUMMARY OF THE INVENTION

An object of the present invention is to address at least the problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of embodiments of the present invention is to provide a touch screen with a soft key that enables input of a specific command by ElectroMagnetic Resonance (EMR).

In accordance with an embodiment of the present invention, a touch screen is provided. The touch screen includes a user interface including a display area and at least one soft key; a touch sensor unit disposed under the display area and the at least one soft key of the user interface, for sensing a touch on the display area or the at least one soft key; a display unit disposed under the touch sensor unit, for outputting a display screen; a first electromagnetic sensor unit disposed under the display unit, for sensing an electromagnetic field incident on the display area; and a second electromagnetic sensor unit physically separated from the first electromagnetic sensor unit, for sensing at least one electromagnetic field incident on the at least one soft key.

In accordance with another embodiment of the present invention, a touch screen is provided. The touch screen includes a user interface including a display area and at least one soft key; a touch sensor unit disposed under the display area of the user interface, for sensing a touch on the display area; a display unit disposed under the first touch sensor unit, for outputting a display screen; a first electromagnetic sensor unit disposed under the display unit, for sensing an electromagnetic field incident on the display area; and a sensor unit physically apart from the first electromagnetic sensor unit, for sensing at least one an electromagnetic field incident on the at least one soft key and a touch on the at least one soft key.

In accordance with a further embodiment of the present invention, a method, performed by an electronic device including a touch screen that has a display area and at least one soft key and is capable of sensing a touch and an electromagnetic field, for controlling the touch screen is provided. The method includes determining whether a touch input locking command has been received; and disabling touch sensing of the display area and the at least one soft key and enabling electromagnetic sensing of the display area and the at least one soft key, upon receipt of the touch input locking command.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same elements will be designated by the same reference numerals although they are shown in different drawings. Further, in the following description of the present invention, a detailed description of known functions and configurations incorporated herein may be omitted for the sake of clarity and conciseness.

FIG. 2is a diagram illustrating a sectional view of a touch screen as a comparative example.

Referring toFIG. 2, the touch screen as a comparative example includes an interface200, a touch sensor unit210, a display220, and an electromagnetic sensor230. The interface200may include a display area110and at least one soft key120.

For firm engagement, the touch screen includes an additional fastener240. Therefore, the size of the electromagnetic sensor230may not be larger than that of the display220. Since there is no electromagnetic sensor for the soft key120, the soft key120may operate only in a capacitive manner.

FIG. 3is a diagram illustrating a sectional view of a touch screen according to an embodiment of the present invention.

Referring toFIG. 3, the touch screen may include an interface300, a touch sensor unit310, a display320, a first electromagnetic sensor unit330, a second electromagnetic sensor unit340, and a light emitter unit350.

The interface300may be a window glass. In order for the interface300to accommodate internal components of the touch screen and to allow a display screen from the display320to penetrate through it as well, the interface300may be formed of a transparent material. In addition, the interface300may be formed of a non-magnetic material and/or formed without a magnetic shield component in order to allow transfer of an incident electromagnetic field to the first or second electromagnetic sensor unit330or340. The interface300may be formed of glass, Poly Methyl Methacrylate (PMMA), polycarbonate, etc. Alternatively, a part of the interface300may be formed of transparent glass, while another part of the interface300may be formed of opaque glass.

The interface300may include the display area110and at least one soft key120.

The touch sensor unit310senses an external touch. The touch sensor unit310may adopt a capacitive scheme for sensing the external touch. The touch sensor unit310may include transparent electrodes and Capacitive-Type (C-type) touch sensors. When a user's body part touches the interface300, the touch sensor unit310senses the touch. The touch sensor unit310may be implemented as a Touch Sensing Panel (TSP).

The touch sensor unit310is disposed near to the bottom surface of the interface300. The touch sensor unit310is mounted on the bottom surface of the display area110and a part of the bottom surface of the soft key120. Accordingly, the touch sensor unit310is able to sense a touch on the display area110or the soft key120.

The display320is disposed near the bottom surface of the touch sensor unit310. More particularly, the display320is near the bottom surface of the part of the touch sensor310corresponding to the display area110of the interface300.

The display320receives an external control signal or graphical signal and outputs a display screen corresponding to the control signal or graphic signal. While the display320may be a Liquid Crystal Display (LCD) module, it will be clearly understood to those skilled in the art that embodiments of the present invention is not limited to any specific type of the display320.

The first electromagnetic sensor unit330senses a magnetic field incident through the interface300and determines a user-selected position based on the sensed magnetic field. The detailed structure of the first electromagnetic sensor unit330is similar to that described herein with reference toFIG. 1B.

More specifically, the first electromagnetic sensor unit330may include a first Printed Circuit Board (PCB), a first controller having at least one Input/Output (I/O) channel, for controlling electromagnetic sensing of the first electromagnetic sensor unit330, and at least one first loop unit extended from the at least one I/O channel of the first controller on a part of the first PCB, for detecting a pen signal, similar to corresponding elements shown inFIG. 1B. The first electromagnetic sensor unit330may be referred to as a coordinate extraction area in that the first electromagnetic sensor unit330senses a position indicated by a pen.

When a specific electromagnetic field is incident, the first loop unit may output an induced voltage and the controller may receive the induced voltage and determine a user-selected position based on the induced voltage.

The first electromagnetic sensor unit330is disposed near to the bottom surface of the display320. As described before in relation to the comparative example, the first electromagnetic sensor unit330may be as large as the display320, to order to allow firm engagement of the entire touch screen. Accordingly, the first electromagnetic sensor unit330may sense only an electromagnetic field incident on the display area110of the interface300, without sensing an electromagnetic field incident on the soft key120.

The second electromagnetic sensor unit340is disposed under the soft key120of the interface300and senses an electromagnetic field incident on the soft key120. The second electromagnetic sensor unit340may be physically apart from the first electromagnetic sensor unit330and sense an electromagnetic field incident on the soft key120without affecting the engagement of the whole touch screen.

More specifically, the second electromagnetic sensor unit340may include a second PCB including at least one sub-area corresponding to the at least one soft key120, a second controller having at least one Input/Output (I/O) channel, for controlling electromagnetic sensing of the second electromagnetic sensor unit340, and at least one second loop unit extended from at the least I/O channel of the second controller on the at least one sub-area of the second PCB, for outputting a voltage induced by an electromagnetic field (not shown). The number of second loops may be equal to the number of soft keys, and arranged at positions corresponding to the soft keys. The second loop units may be referred to as an on/off detection area in that the second loop units detect selection of specific soft keys, but do not detect an accurate position indicated by a pen, significantly beyond that required in order to determine which specific soft keys are selected.

When a specific electromagnetic field is incident on a soft key120, the second loop units may output induced voltages according to the electromagnetic field and the second controller may identify the user-selected soft key based on the induced voltages. For example, the second controller may identify, as a user-selected loop unit, a second loop unit having a largest magnitude from among the magnitudes of induced voltages output from the at least one second loop unit, and accordingly identify the user-selected soft key.

The light emitter unit350is disposed under a part of the interface300corresponding to the at least one soft key120. For example, if the touch screen includes four soft keys, the light emitter unit350may include four light emitters arranged under the interface300having the four soft keys, for illuminating the four soft keys.

Although the light emitter unit350may be configured with Light Emitting Diodes (LEDs), embodiments of the present invention are not limited to any specific type of the light emitter unit350, and other types of lighting devices may be used in accordance with embodiments of the present invention.

When the second electromagnetic sensor unit340determines a user-selected soft key, the light emitter unit350emits light to illuminate the user-selected soft key. For example, if the touch screen includes first to fourth soft keys and the second electromagnetic sensor unit340determines the second soft key as selected by a user, the light emitter unit350is controlled to illuminate the second soft key.

Since the touch screen further includes the second electromagnetic sensor unit340that can sense an electromagnetic field incident on a soft key without affecting engagement of the whole touch screen, the user can select a soft key by an electromagnetic input as well as a touch input.

FIG. 4is a diagram illustrating a sectional view of a touch screen according to another embodiment of the present invention.

Referring toFIG. 4, the touch screen include an interface400, a first touch sensor unit410, a display420, a first electromagnetic sensor unit430, a sensor unit440, and a light emitter unit450. Components that are the same or similar to corresponding components of the touch screen illustrated inFIG. 3may not be described again with respect toFIG. 4, or may be described briefly.

The first touch sensor unit410is mounted on the bottom surface of the display area110of the interface400. The touch screen illustrated inFIG. 4differs from the touch screen illustrated inFIG. 3in that the first touch sensor unit410senses a touch input to the display area110, but does not sense a touch input to the at least one soft key120. Therefore, the first touch sensor unit410independently senses a touch on the display area110.

The display420is mounted on the bottom surface of the first touch sensor unit410. As described above, since the first touch sensor unit410senses only a touch on the display area110, the size of the first touch sensor unit410may be about equal to the size of the display420.

The first electromagnetic sensor unit430is mounted on the bottom surface of the display420. The first electromagnetic sensor unit430senses an electromagnetic field input to the display area110and the size of the first electromagnetic sensor unit430may be about equal to the size of the display420.

The sensor unit440is mounted on the bottom surface of the soft key120. The sensor unit440includes a second touch sensor unit441for sensing a touch on the at least one soft key120, a second electromagnetic sensor unit442for sensing an electromagnetic field incident on the at least one soft key120, and a controller443for controlling the second touch sensor unit441and the second electromagnetic sensor unit442. Meanwhile, the touch screen may further include a connector for connecting the second touch sensor unit441to the second electromagnetic sensor unit442.

According to the embodiment of the present invention illustrated inFIG. 4, the second touch sensor unit441and the second electromagnetic sensor unit442may be physically incorporated. As illustrated inFIG. 4, the second touch sensor unit441is mounted on the bottom surface of the at least one soft key120of the interface300. The second electromagnetic sensor unit442is connected from below to the second touch sensor unit441. To sense a variation in capacitance, the second touch sensor unit441is positioned closer to the interface300than the second electromagnetic sensor unit442.

The light emitter unit450is mounted on the top surface of the second electromagnetic sensor unit442, and accordingly is positioned under the second touch sensor unit441. As stated before with reference toFIG. 3, when the second touch sensor unit441or the second electromagnetic sensor unit442identifies a user-input soft key, the light emitter unit450is controlled to illuminate the user-input soft key.

Since the touch screen further includes the second electromagnetic sensor unit442that can sense an electromagnetic field incident on a soft key without affecting engagement of the whole touch screen, the user can select a soft key by an electromagnetic input as well as a touch input.

FIG. 5Ais a diagram illustrating a connection relationship among a controller, a display area loop unit, and a soft key loop unit according to an embodiment of the present invention.

Referring toFIG. 5A, a controller510may receive induced voltages from a display loop unit520and a soft key loop unit530and determine a user-selected loop unit based on the induced voltages. The controller510may determine a loop unit that outputs an induced voltage with a largest magnitude as a user-selected loop unit.

For example, if a second soft key loop unit532included in the soft key loop unit530outputs an induced voltage with a largest magnitude, the controller510may determine that the user has selected a second soft key using an electromagnetic tool such as an EMR pen.

While the controller510is shown inFIG. 5Aas physically apart from the display area loop unit520and the soft key loop unit530, a control circuit such as a microprocessor may be mounted in the display area loop unit520and thus the controller510and the display area loop unit520or the controller510and the soft key loop unit530may be physically incorporated.

FIG. 5Bis a diagram illustrating a connection relationship among the controller, the display area loop unit, and the soft key loop unit according to another embodiment of the present invention.

Referring toFIG. 5B, the controller510, the display area loop unit520, and the soft key loop unit530may be implemented in the form of chips integrated on PCBs.

The controller510may include a first connector511for connecting to the display area loop unit520and a second connector512for connecting to the soft key loop unit530. While the first and second connectors511and512may be shaped into gold fingers, embodiments of the present invention are not limited to this specific configuration of the connectors511and512, and other configurations may be used in accordance with embodiments of the present invention. While not shown, a chip such as a microprocessor may be mounted on the controller510, such that the chip is used for determining a user-selected soft key based on the magnitude of an induced voltage that each loop unit provides to the first and second connectors511and512.

The display area loop unit520is disposed according to the position of the display area of the touch screen and includes a loop unit522. When a specific electromagnetic field is incident on the display area, the display area loop unit520outputs an induced voltage from the loop unit522to a connector521. The connector521outputs the received induced voltage to the first connector511.

The soft key loop unit530is disposed according to the positions of soft keys in the touch screen and includes loop units532. When a specific electromagnetic field is incident on a soft key, the soft key loop unit530outputs induced voltages from the loop units532to a connector531. The connector531outputs the received induced voltages to the second connector512.

FIG. 5Cis a diagram illustrating a connection relationship among the controller, the display area loop unit, and the soft key loop unit according to another embodiment of the present invention.

In a manner similar to that shown with reference toFIG. 5B, in the connection relationship according toFIG. 5C, the display area loop unit521and the soft key loop unit522are arranged on the same PCB. However, in contrast toFIG. 5B, the display area loop unit521and the soft key loop unit522ofFIG. 5Cuse independent channels, and therefore, induced voltages output from the display area loop unit521and the soft key loop unit522may be processed independently.

FIGS. 6A and 6Bare diagrams illustrating a structure for conducting a voltage for electromagnetic induction and a structure for conducting induced voltages according to embodiments of the present invention.

FIG. 6Ais a diagram illustrating a plurality of loop units602,603,604, and605for conducting current for electromagnetic induction and conducting induced voltages. The plurality of loops602,603,604, and605are arranged at positions corresponding to respective soft keys.

A controller (not shown), which is connected to the plurality of loops602,603,604and605and controls electromagnetic sensing, uses the plurality of loops602,603,604, and605as current conduction means by conducting a predetermined current through the loops. The controller also uses the plurality of loops602,603,604, and605as induced voltage conduction means by discontinuing a current conduction during a first time period and receiving an induced voltage from one of the loops602,603,604, and605during a second time period.

More specifically, the controller may use the plurality of loops602,603,604, and605as current conduction means or induced voltage conduction means in time division.

FIG. 6Bis a diagram illustrating a plurality of loops for conducting current for electromagnetic induction and conducting induced voltages and an output loop unit arranged on a PCB, through which the current for electromagnetic induction flows, according to an embodiment of the present invention. The plurality of loops604,605,606and607are arranged at positions corresponding to respective soft keys.

The plurality of loops604,605,606, and607and the output loop unit603are connected to a controller. The controller conducts a predetermined current for electromagnetic induction through the output loop unit and receives induced voltages from the plurality of loops604,605,606, and607.

FIG. 7is a diagram illustrating a touch screen having an electromagnetic shield according to an embodiment of the present invention.

Referring toFIG. 7, a light emitter unit703is mounted on a second electromagnetic sensor unit702having the configuration illustrated inFIG. 3. Since an external magnetic field may cause signal distortion to the touch screen after the second electromagnetic sensor unit702senses an electromagnetic field, the touch screen may further include an electromagnetic shield701under the second electromagnetic sensor unit702.

The electromagnetic shield701prevents magnetic field disturbance. For example, the electromagnetic shield701may prevent magnetic field disturbance caused by an Eddy current at a conductive metal.

FIGS. 8A and 8Bare diagrams illustrating a touch screen further having a light guide according to an embodiment of the present invention.

Referring toFIGS. 8A and 8B, a second electromagnetic sensor unit802is mounted on an electromagnetic shield801and a light emitter unit804is mounted on the second electromagnetic sensor unit802. The touch screen further includes a light guide803near one side of the light emitter unit804on the second electromagnetic sensor unit802.

Therefore, the touch screen may illuminate a soft key using the light emitter unit804having a single light emitter and the light guide803, instead of using the same number of light emitters as the number of soft keys.

FIGS. 9A, 9B and 9Care diagrams illustrating touch input locking and touch input unlocking according to an embodiment of the present invention.

Referring toFIG. 9A, an icon901corresponding to a touch input locking command is displayed in a display area. A user executes the touch input locking command by touching the icon901or applying a specific electromagnetic input to the icon901.

When the touch input locking command is executed, a touch screen900disables touch sensing of the display area and touch sensing of at least one soft key, while enabling electromagnetic sensing of both the display area and the at least one soft key.

FIG. 9Bis a diagram illustrating a screen displayed on the touch screen900, after the touch input locking command is executed. In the locked state, the icon901set to “Lock” illustrated inFIG. 9Ais changed to “Unlock”.

The user may unlock the locked state of touch input by selecting the “Unlock” icon901. Upon selection of the “Unlock” icon901, the touch screen900enables touch sensing of the display area and the at least one soft key.

Since touch sensing of the display area and the at least one soft key has been disabled, the user selects the icon901inFIG. 9Busing an electromagnetic tool such as an EMR pen. According to another embodiment of the present invention, if the touch screen900disables touch sensing of the remaining area except for the icon901, touch sensing of the icon901remains enabled, the user may unlock the locked touch sensing by selecting the icon901through a touch input as well as an electromagnetic input.

FIG. 9Cis a diagram illustrating an operation for enabling touch sensing according to another embodiment of the present invention.

Referring toFIG. 9C, in a state where touch sensing is disabled, the user enables touch sensing by making a predetermined motion such as touching an upper end of the display area and dragging the touch with a user's body part, such as a fingertip. Thus, the user may unlock touch sensing later through a touch input as well as an electromagnetic input. Meanwhile, the touch screen may provide a menu screen with a touch enable icon through a predetermined operation as described above, and, upon selection of the icon, the touch screen may enable touch sensing.

FIG. 10is a flowchart illustrating a method for controlling a touch screen having a display area and at least one soft key, which can sense a touch and an electromagnetic field according to an embodiment of the present invention.

Referring toFIG. 10, the touch screen determines whether a touch input locking command has been received, in step S1010.

Upon receiving the touch input locking command, the touch screen disables touch sensing of the display area and at least one soft key, in step S1020and enables electromagnetic sensing of the display area and the at least one soft key, in step S1030.

Subsequently, the touch screen determines whether a touch input unlocking command has been received, in step S1040.

Upon receiving the touch input unlocking command, the touch screen enables touch sensing of the display area and the at least one soft key, in step S1050.

The touch input locking command may be generated by touching or applying an electromagnetic field to a predetermined part of the display area. In addition to, or as an alternative to applying the electromagnetic field, the touch input unlocking command may be generated by applying an electromagnetic field to a predetermined part of the display area.

However, touch sensing of the remaining area except for at least one specific part of the display area may be disabled in the step of disabling touch sensing of the display area and the at least one soft key. In this case, the touch input unlocking command may be generated by touching or applying an electromagnetic field to the specific part of the display area.

FIG. 11is a flowchart illustrating a method for selecting a mode for enabling/disabling EMR sensors and touch sensors according to an embodiment of the present invention.

Referring toFIG. 11, the user selects one of a first, second, or third mode. The user may select a menu corresponding to an intended mode displayed on the touch screen. Alternatively, the user may be provided with a mode selection screen by making a predetermined motion as described before with reference toFIG. 9Cand may select a mode on the mode selection menu, in step S1110.

Upon selection of the first mode, in step S1120, the touch screen enables EMR sensors of the display area and the soft key area, while disabling touch sensors of the display area and the soft key area, in step S1121.

Upon selection of the second mode, in step S1130, the touch screen enables the EMR sensors of the display area and the soft key area, while enabling the touch sensors of the display area and disabling the touch sensors of the soft key area, in step S1131.

Upon selection of the third mode, in step S1140, the touch screen enables all of the EMR sensors, in step S1141.

In step S1150, the user may reselect a mode by selecting a menu or making a predetermined motion as described above. Therefore, the user may control an input scheme for the touch screen, while selecting various modes.

As is apparent from the above description of embodiments of the present invention, a touch screen having a soft key that enables a specific command input through electromagnetic resonance can be provided. Since a soft key can operate in both of capacitive and electromagnetic resonance schemes in a touch screen according to embodiments of the present invention, a specific position may be selected on the touch screen by a touch input or an electromagnetic input. In addition, the touch input function of a soft key can be disabled via input of a touch input locking command. Therefore, an EMR pen can be used without interference from a touch detected on a soft key.