JP4093972B2 - Touch panel display device and electronic device including the same - Google Patents

Description

  The present invention relates to a touch panel display device and an electronic device including the display device, and particularly relates to noise suppression in an electronic device with a call function including a touch panel display device.

  2. Description of the Related Art Conventionally, an electronic device with a call function including a touch panel display device is known. FIG. 2 is a partial cross-sectional view of the electronic apparatus. As shown in FIG. 2, a part of the electronic apparatus has a structure in which a touch panel 100 and an image display unit 300 including a liquid crystal layer 32 for displaying an image are bonded to each other. The touch panel 100 includes an upper electrode 10 that receives input (pressing) with a pen or the like, and a lower electrode 12 that is disposed to face the upper electrode 10 with an air layer 11 interposed therebetween. In the image display unit 300, the front polarizing plate 30 is provided to face the lower electrode 12 of the touch panel 100 with the air layer 20 interposed therebetween. The lower electrode 12 includes a position detection circuit (not shown) that detects a position pressed with a pen or the like on the touch panel 100, and a display drive circuit that generates a drive signal for driving the liquid crystal in the image display unit 300. (Not shown) can be electrically connected. When the touch panel 100 is pressed from the outside with a pen or the like, the upper electrode 10 and the lower electrode 12 come into contact with each other, and the pressed position (coordinates) on the touch panel 100 is detected by the position detection circuit. Then, in accordance with the coordinates detected by the position detection circuit, the display drive circuit generates a drive signal for driving the liquid crystal. Thereby, the liquid crystal is driven and an image is displayed on the image display unit 300. In general, the touch panel 100 and the image display unit 300 are fixed by a chassis or the like.

In such a liquid crystal display device, when an input operation with a pen or the like is performed, the lower electrode 12 of the touch panel 100 and the front polarizing plate 30 of the image display unit 300 may come into contact with each other. At this time, contact charging, peeling charging, frictional charging, and the like occur due to the contact. Here, by supplying a drive signal to the image display unit in order to drive the liquid crystal, a potential difference is generated between the lower electrode 12 and the front polarizing plate 30, but electric field energy (electric field strength) generated due to the potential difference is generated. (E) is represented by “E”, the charge amount in the air layer 20 between the touch panel 100 and the image display unit 300 is represented by “Q”, and the force that vibrates the touch panel 100 is represented by “F”. To do.
F = QE (1)

  When the contact between the lower electrode 12 and the front polarizing plate 30 is repeated, the charge amount Q increases, and the force F that vibrates the touch panel 100 increases accordingly. Generally, it is said that the human audible range is 20 Hz to 20 kHz, and if the frequency of vibration based on the force F that vibrates the touch panel 100 is included in the audible range, the human ear can hear it as noise. When such noise (hereinafter referred to as “sound noise”) is generated during a call, it is difficult to hear the voice of the other party, so that a comfortable call is hindered. For this reason, an electronic device including a circuit for suppressing sound noise (hereinafter referred to as “sound noise suppression circuit”) has also been proposed.

  FIG. 6 is a configuration diagram of a conventional sound noise suppression circuit 200. The sound noise suppression circuit 200 includes a switching unit 400 and a touch panel pressing determination unit 700. A position detection circuit 500 is connected to the terminal 2 of the switching unit 400, and a display drive circuit 600 is connected to the terminal 3. A lower electrode 12 is connected to the terminal 4. The switching unit 400 connects either the terminal 2 or the terminal 3 to the terminal 4 in response to a switch selection signal S described later output from the touch panel pressing determination unit 700. The touch panel press determination unit 700 determines whether or not the touch panel 100 is in a pressed state based on whether or not the upper electrode 10 and the lower electrode 12 are in contact with each other, and a signal indicating the result of the determination is a switch selection signal. S is output.

  Next, the operation of the conventional sound noise suppression circuit 200 will be described. In the sound noise suppression circuit 200, a signal indicating whether or not the touch panel 100 is in a pressed state is output from the touch panel pressing determination unit 700 as the switch selection signal S, and the switch selection signal S is input to the switching unit 400. Then, when the switch selection signal S indicates that the touch panel 100 is in the pressed state, the terminal 4 and the terminal 2 are connected as shown in FIG. Thereby, since the lower electrode 12 and the position detection circuit 500 are electrically connected, the pressed position (coordinates) on the touch panel 100 is detected. At this time, sound noise is generated by supplying the drive signal to the image display unit 300. On the other hand, when the switch selection signal S indicates that the touch panel 100 is not in the pressed state, the terminal 4 and the terminal 3 are connected as shown in FIG. As a result, the lower electrode 12 and the display drive circuit 600 are electrically connected, so that the drive signal is supplied not only to the image display unit 300 but also to the lower electrode 12 in the touch panel 100. . As a result, the lower electrode 12 in the touch panel 100 and the front polarizing plate 30 in the image display unit 300 become the same potential, and the electric field energy (electric field strength) becomes almost zero. Thereby, the force F which vibrates the touch panel 100 is suppressed, and sound noise is suppressed. Usually, when an input operation is performed on the touch panel 100, a call is not performed. For this reason, even if sound noise occurs when the touch panel 100 is in the pressed state as described above, it is allowed as far as the normal use state is concerned.

Japanese Patent Application Laid-Open No. 9-149157 discloses a communication terminal device that prevents noise accompanying an input operation with a pen or the like from being mixed into a conversation. In this communication terminal device, the noise component is removed by the noise component removing unit from the sound signal input to the microphone, and the sound signal after the noise component removal is transmitted to the communication partner side. As a result, only a pure voice signal from which noise components have been removed is transmitted to the other party, and noise is suppressed from being mixed into the conversation.
JP-A-9-149157

  However, when a call is made using the electronic device as described above, the user's ear may come into contact with the touch panel of the electronic device. In such an electronic device provided with the conventional sound noise suppression circuit described above, the operation when the touch panel is in a pressed state is performed in this case, so that the user of the electronic device can hear the sound noise. Further, the communication terminal device disclosed in Japanese Patent Laid-Open No. 9-149157 prevents only sound noise from being mixed into the conversation due to an input operation or the like by transmitting only a pure audio signal to the other party. Yes, it does not prevent the user on the sound noise generating side from hearing sound noise.

  Therefore, in the present invention, even if there is an unintended contact with the touch panel of the user such as an ear touching the touch panel during a call, the generation of sound noise is suppressed and the user can talk comfortably. It is an object of the present invention to provide an electronic device with a sum function equipped with a display device.

According to a first aspect of the present invention, there is provided a touch panel including an upper electrode that receives input from an external press and a lower electrode provided to face the upper electrode, an image display unit disposed to face the touch panel, A display drive unit that generates a drive signal for displaying an image on the image display unit and supplies the drive signal to the image display unit. And
The lower electrode and the display driving means are connected when the call function is in an effective state.

A second invention is an electronic device having a call function, comprising the display device according to the first invention,
Call determination means for determining whether or not the call function is in an effective state; and switching means for switching the connection destination of the lower electrode,
The switching means connects the lower electrode and the display driving means when the call function is in an effective state based on a determination result by the call determination means.

According to a third invention, in the second invention,
Position detecting means for detecting the position of the pressing, and touch panel pressing determining means for determining whether or not the touch panel is in a pressed state,
The switching means is
When the call determination means determines that the call function is not valid and the touch panel press determination means determines that the touch panel is pressed, the lower electrode and the position detection means Connect the
When the call determination means determines that the call function is not valid and the touch panel press determination means determines that the touch panel is not pressed, the lower electrode and the display drive means Is connected.

  According to the first aspect, when the call function is valid, the lower electrode of the touch panel and the display driving means are connected. For this reason, during a call, a drive signal for image display is supplied not only to the image display means but also to the lower electrode of the touch panel. When the drive signal is supplied only to the image display means, a potential difference is generated between the touch panel and the image display means, and the touch panel vibrates. However, when the drive signal is supplied also to the lower electrode of the touch panel, the touch panel and the image display means are supplied. The potential difference between and becomes almost zero, and the force that vibrates the touch panel is suppressed. Thereby, even if the user's unintended contact with the touch panel is during a call, the generation of sound noise is suppressed, and the user can make a call comfortably.

  According to the second aspect, when the call function of the electronic device is valid, the lower electrode of the touch panel and the display driving means are connected by the switching means. Thereby, the same effect as that of the first invention can be obtained.

  According to the third aspect, in a state where the call function of the electronic device is invalid, the lower electrode and the position detection unit are connected when the touch panel is pressed, and the lower electrode and the display are displayed when the touch panel is not pressed. The driving means is connected. For this reason, at the time of non-calling, the pressed position of the touch panel is detected by the position detecting means, and an image is displayed according to the pressed position. On the other hand, when the call function of the electronic device is valid, the lower electrode of the touch panel and the display driving means are connected as in the second aspect of the invention, so that the generation of sound noise is suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

<1. Configuration of liquid crystal display device>
FIG. 1 is a block diagram showing an overall configuration of an electronic device with a calling function (for example, a mobile phone) provided with a touch panel display device according to an embodiment of the present invention. The electronic device includes a touch panel 100, an image display unit 300, a switching unit 400, a position detection circuit 500, a display drive circuit 600, a touch panel press determination unit 700, and a call determination unit 800. As shown in FIG. 1, a sound noise suppression circuit 200 for suppressing sound noise generated in response to an input operation on the touch panel 100 is configured by the switching unit 400, the touch panel press determination unit 700, and the call determination unit 800. Yes. FIG. 2 is a partial cross-sectional view of a part constituting the touch panel 100 and the image display unit 300 in this electronic apparatus. As shown in FIG. 2, this part has a structure in which a touch panel 100 and an image display unit 300 including a liquid crystal layer 32 for displaying an image are bonded to each other. The touch panel 100 includes an upper electrode 10 that receives input from a pen or the like, and a lower electrode 12 that is disposed so as to face the upper electrode 10 with an air layer 11 therebetween. The image display unit 300 is provided with a front polarizing plate 30, a glass panel 31, a liquid crystal layer 32, a glass panel 33, a back polarizing plate 34, and a backlight unit 35 in order from the side where the touch panel 100 is disposed. Further, the lower electrode 12 in the touch panel 100 and the front polarizing plate 30 in the image display unit 300 are disposed to face each other with the air layer 20 interposed therebetween.

  The touch panel 100 receives input (pressing) with a pen or the like. When the upper electrode 10 of the touch panel 100 is pressed with a pen or the like, the upper electrode 10 and the lower electrode 12 come into contact with each other. The touch panel press determination unit 700 determines whether or not the touch panel 100 is in a pressed state based on whether or not the upper electrode 10 and the lower electrode 12 are in contact with each other. The position detection circuit 500 detects the position (coordinates) of the pen at the time of input based on the contact position between the upper electrode 10 and the lower electrode 12. The call determination unit 800 determines whether or not the call function is valid based on the history information of the pressing state of a reception button and an end button (not shown) provided on the electronic device (hereinafter referred to as a call). The state in which the function is effective is referred to as “call state”, and the state in which the call function is not in effect is referred to as “non-call state”). Based on the result determined by the touch panel press determination unit 700 and the result determined by the call determination unit 800, the switching unit 400 electrically connects either the position detection circuit 500 or the display drive circuit 600 to the lower electrode 12. Connect to. The display drive circuit 600 generates a drive signal for driving the liquid crystal according to the coordinates detected by the position detection circuit 500 in advance. As a result, the liquid crystal is driven and a desired image is displayed on the image display unit 300.

<2. Configuration of sound noise suppression circuit>
Next, the configuration of the sound noise suppression circuit 200 will be described with reference to FIG. The sound noise suppression circuit 200 includes a switching unit 400, a touch panel press determination unit 700, and a call determination unit 800. The switching unit 400 includes a switch selection unit 40 and an AND circuit 41. The position detection circuit 500 is connected to the terminal 2 of the switch selection unit 40, the display drive circuit 600 is connected to the terminal 3, and the lower electrode 12 is connected to the terminal 4. A touch panel press determination unit 700 is connected to the input terminal 5 of the AND circuit 41, a call determination unit 800 is connected to the input terminal 6, and a switch selection unit 40 is connected to the output terminal 7. The switch selection unit 40 receives a switch selection signal S (described later) output from the output terminal 7 of the AND circuit 41. In the switch selection unit 40, the terminal 4 and the terminal 2 are connected when the switch selection signal S is high level, and the terminal 4 and the terminal 3 are connected when the switch selection signal S is low level.

<3. Operation of sound noise suppression circuit>
Next, the operation of the sound noise suppression circuit will be described. FIG. 3 is a diagram for explaining the operation of the sound noise suppression circuit 200 in the non-calling state. This electronic device is provided with a reception button and an end button, and the user presses the reception button at the start of the call and presses the end button at the end of the call. Thereby, it can be judged whether it is a call state or a non-call state based on the history information of the pressing state of the reception button and the end button. In the present embodiment, the call determination unit 800 determines whether the call is in a call state or a non-call state based on the history information. On the other hand, as described above, the touch panel press determination unit 700 determines whether or not the touch panel 100 is in a pressed state.

  As a result of the determination by the call determination unit 800, when the call is not in a call state, a high level signal is input to the input terminal 6 of the AND circuit 41. On the other hand, when the touch panel press determination unit 700 determines that the touch panel 100 is in the pressed state, a high level signal is input to the input terminal 5 of the AND circuit 41, and it is determined that the touch panel 100 is not in the pressed state. A low level signal is input. The AND circuit 41 outputs a signal indicating the result of the AND operation of the input signals input to the input terminal 5 and the input terminal 6 from the output terminal 7 as the switch selection signal S. In the non-calling state, since a high level signal is always input to the input terminal 6 as described above, the switch selection signal S is at a high level when the touch panel 100 is in the pressed state, and the touch panel 100 is not in the pressed state. Sometimes low level. As described above, since the terminal 4 and the terminal 2 are connected when the switch selection signal S is at a high level, and the terminal 4 and the terminal 3 are connected when the switch selection signal S is at a low level, the touch panel 100 is in a pressed state. In some cases, the lower electrode 12 is electrically connected to the position detection circuit 500, and when the touch panel 100 is not in the pressed state, the lower electrode 12 is electrically connected to the display drive circuit 600. Thereby, the pressed position on the touch panel 100 is detected by the position detection circuit 500, and an image is displayed on the image display unit 300 according to the pressed position.

  Next, the operation of the sound noise suppression circuit 200 during a call state will be described with reference to FIG. When the call determination unit 800 determines that a call is in progress, a low level signal is input to the input terminal 6 of the AND circuit 41. Therefore, when in a call state, the switch selection signal S is at a low level regardless of the pressed state of the touch panel 100. Since the switch selection signal S is at a low level, the terminal 4 and the terminal 3 are connected in the switch selection unit 40. That is, the lower electrode 12 is electrically connected to the display drive circuit 600 regardless of the pressed state of the touch panel 100. For this reason, when in a call state, even if the touch panel 100 is pressed, the lower electrode 12 and the position detection circuit 500 are not electrically connected, and the lower electrode 12 and the display drive circuit 600 are always electrically connected. Is done.

  In the above description, it is assumed that a low level signal is output from the call determination unit 800 in a call state and a high level signal is output from the call determination unit 800 in a non-call state. However, the present invention is not limited to this. As shown in FIG. 5, by providing a NOT gate 8 between the call determination unit 800 and the input terminal 6, a high level signal is output from the call determination unit 800 in a call state, and a call is made in a non-call state. The present invention can also be applied to a configuration in which a low level signal is output from the determination unit 800.

<4. Effect>
As described above, according to the above-described embodiment, in an electronic device including a touch panel display device, a drive signal for driving a display element is displayed regardless of whether the touch panel 100 is pressed or not during a call state. It is supplied not only to the drive circuit 600 but also to the lower electrode 12 in the touch panel 100. When the drive signal is supplied only to the image display unit 300, a potential difference is generated between the touch panel 100 and the image display unit 300, and vibration is generated. However, the drive signal is also supplied to the lower electrode 12 in the touch panel 100. As a result, the potential difference between the touch panel 100 and the image display unit 300 becomes substantially zero, the force that vibrates the touch panel 100 is suppressed, and sound noise is suppressed. As a result, even if there is an unintended contact with the touch panel 100 such as the user's ear touching the touch panel 100 during a call, the generation of sound noise is suppressed, so that the user is comfortable without feeling uncomfortable. You can make a call.

<5. Other>
In the above embodiment, the electronic apparatus including the transmissive liquid crystal display device having the backlight unit 35 has been described as an example. However, the present invention is not limited to this, and the backlight unit 35 is unnecessary. The present invention can also be applied to an electronic device provided with a reflective liquid crystal display device. In the above-described embodiment, the electronic apparatus provided with the liquid crystal display device has been described as an example. However, the present invention is not limited to this, and a display other than the liquid crystal display device such as an organic EL (Electroluminescence) display device. The present invention can also be applied to an electronic device provided with the device. Furthermore, in the above embodiment, it is configured to determine whether or not the telephone is in a call state based on history information on the pressing state of the reception button and the end button provided in the electronic device, but the present invention is not limited to this. Is not to be done. For example, the present invention can also be applied to a configuration in which it is determined whether or not a call state is established based on opening / closing of a cover of an electronic device or a storage state of an antenna in an antenna storage unit.

It is a block diagram which shows the whole structure of the electronic device with a call function provided with the touchscreen type display apparatus which concerns on one Embodiment of this invention. It is a fragmentary sectional view of the portion which constitutes a touch panel and an image display part in the above-mentioned embodiment. It is a figure for demonstrating operation | movement of the sound noise suppression circuit at the time of a non-call state in the said embodiment. It is a figure for demonstrating operation | movement of the sound noise suppression circuit at the time of a telephone call state in the said embodiment. It is a block diagram of the sound noise suppression circuit in a modification. It is a figure for demonstrating operation | movement of the sound noise suppression circuit when a touch panel is a press state in a prior art example. It is a figure for demonstrating operation | movement of the sound noise suppression circuit when a touch panel is not a press state in a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Upper electrode 12 ... Lower electrode 100 ... Touch panel 200 ... Sound noise suppression circuit 300 ... Image display part 400 ... Switching part 500 ... Position detection circuit 600 ... Display drive circuit 700 ... Touch panel press judgment part 800 ... Call judgment part

Claims (3)

A touch panel composed of an upper electrode that receives an input by pressing from the outside and a lower electrode provided to face the upper electrode, an image display means disposed to face the touch panel, and an image on the image display means A display drive unit that generates a drive signal for display and supplies the drive signal to the image display unit, and is a touch panel display device used in an electronic device having a call function,
The display device, wherein the lower electrode and the display driving means are connected when the call function is in an effective state. An electronic device having a call function, comprising the display device according to claim 1,
Call determination means for determining whether or not the call function is in an effective state; and switching means for switching the connection destination of the lower electrode,
The electronic device characterized in that the switching means connects the lower electrode and the display driving means when the call function is in an effective state based on a determination result by the call determination means. Position detecting means for detecting the position of the pressing, and touch panel pressing determining means for determining whether or not the touch panel is in a pressed state,
The switching means is
When the call determination means determines that the call function is not valid and the touch panel press determination means determines that the touch panel is pressed, the lower electrode and the position detection means Connect the
When the call determination means determines that the call function is not valid and the touch panel press determination means determines that the touch panel is not pressed, the lower electrode and the display drive means The electronic device according to claim 2, wherein the electronic device is connected.

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