Patent Description:
In general, when a user operates a graphical user interface (GUI) displayed on a display including a touch panel, a pressing amount is detected in addition to a touch on the touch panel, and it is determined that the GUI has been pressed when the pressing amount exceeds a threshold value. Since a detection of a pressing amount is additionally used for a determination as to whether a pressing operation has been performed, a reliable pressing operation may be requested to the user.

When the user operates the touch panel, a pressing amount detected by a sensor may be instantaneously increased due to electromagnetic noise or external vibration noise. When the pressing amount which is instantaneously increased due to generation of noise exceeds a threshold value, it is mistakenly determined that a pressing operation has been performed although an amount of pressing performed by the user does not actually reach the threshold value. In general, to avoid this problem, a low pass filter (LPF), such as a moving average filter (MAF), is disposed to perform moving average on pressing amounts successively detected by the sensor for smoothing so that an adverse effect of the noise is reduced.

<FIG> is a diagram schematically illustrating occurrence of false detection of a pressing operation caused by noise and a countermeasure using an MAF. In <FIG>, an axis of abscissae denotes an elapsed time and an axis of ordinates denotes a pressing amount. In <FIG>, a state in which pressure is gradually increased after a pressing operation is started on the touch panel is illustrated. For simplicity of description, it is assumed that the user increases pressure at a constant rate with time (a pressing amount is increased at a constant rate).

In the example of <FIG>, noise is generated twice while a pressing amount is gradually increased as the user gradually increases pressure on the touch panel. When the moving average process is not performed by the MAF, a pressing amount which is instantaneously increased due to the noise generated in the second time exceeds a threshold value, and therefore, it is mistakenly determined that a pressing operation is performed at this time point. On the other hand, when the moving average process is performed, a pressing amount which is smoothed by the moving average does not exceed the threshold value even when a detection value of a pressing amount instantaneously becomes larger than the threshold value due to the noise generated in the second time, and therefore, the false detection of determining that the pressing operation is performed at this time point may be avoided.

<CIT> discloses a touch operation detection apparatus which avoids false detection of a touch operation caused by noise. Specifically, the touch operation detection apparatus disclosed in <CIT> detects a touch on an operation surface as a touch operation when a moving distance and a touch load which are detected in a touch position on the touch panel satisfy a predetermined relationship. In this method, when noise or the like is detected, a moving distance and a touch load do not satisfy the predetermined relationship, and therefore, a touch operation is not mistakenly detected.

Furthermore, an electronic apparatus having a plurality of threshold values set for performing a predetermined process and capable of detecting pressure on a touch panel in a number of stages has been used, and in the electronic apparatus, the plurality of threshold values are set such that differences between the threshold values are successively reduced as a pressing amount is increased (refer to <CIT>, for example). In this way, a burden given to the user until pressure in upper stages is detected may be reduced and occurrence of an erroneous operation in which pressure is instantaneously detected in a plurality of stages when the user only lightly touches the touch panel in an unintentional manner may be avoided.

As described above, by obtaining a moving average of pressing amounts successively detected by the sensor, even when an output value of the sensor is instantaneously increased to exceed the threshold value due to noise, false detection of mistakenly determining that a pressing operation is performed at this time point may be avoided. However, as illustrated in <FIG>, in a case where the user performs an operation of strongly pressing the touch panel in a comparatively short period of time (a so-called "tap operation"), even when a pressing amount output from the sensor is larger than the threshold value, a pressing amount obtained by the moving average process does not exceed the threshold value, and therefore, there arises a problem in that a tap operation is not detected.

<CIT> discloses systems and methods for adaptively interpreting a user's intent based on parameters supplied by a touch-sensitive input device. A processor receives a pressure signal indicating a pressure from an input device, such as a touchpad, compares the pseudo pressure signal to a pressure threshold value, and outputs a signal if the pseudo pressure signal is greater than the pressure threshold value. In another embodiment, the processor also calculates the speed of movement of a conductor, for instance a user's finger, across the input device, and compares the speed to a threshold. If the speed is greater than the threshold, the processor determines that although the pressure may be great enough to signal a press, no press is intended. The various parameters supplied by the input device may be digitally filtered to increase the accuracy of the determination of user intent.

<CIT> discloses a touch-pressure detection unit which detects a touch pressure that changes according to a degree of a touch operation on a display surface of a display unit. An interrupt necessity determination unit determines whether or not an interrupt is necessary on the basis of a change period and change amount of the touch pressure. In the case where an interrupt is unnecessary, the ratchet function output unit inputs the touch pressure to a predetermined ratchet function, and provides an output value of the ratchet function to a game-character-action-amount determination unit which determines a movement speed of the game character C according to the output value of the ratchet function.

<CIT> discloses devices and methods for processing and disambiguating touch inputs using intensity thresholds based on prior input intensity. An object of the present invention is to avoid false detection of a pressing operation caused by an instantaneous change of a pressing amount due to noise when a pressing operation of gradually increasing pressure in a comparatively long period of time is performed and to avoid a case where a pressing operation is not detected when a pressing operation of performing a strong press in a comparatively short period of time is performed. The invention relates to a pressing operation detection device and method according to the appended claims. Embodiments are disclosed in the dependent claims.

A determination process of easily detecting a pressing operation in response to an instantaneous change of a pressing amount in a short period of time or a determination process of not easily detecting a pressing operation in response to an instantaneous change of a pressing amount may be selected in accordance with a touch time of touching on the operation unit performed by the user. By this, according to the present invention, false detection of a pressing operation caused by an instantaneous change of a pressing amount due to noise when a pressing operation of gradually increasing pressure for a comparatively long period of time is performed may be avoided and a case where a pressing operation is not detected when a pressing operation of performing a strong press in a comparatively short period of time is performed may be avoided.

<FIG> is a diagram schematically illustrating an example of a configuration of an in-vehicle apparatus including a pressing operation detection device according to an embodiment. As illustrated in <FIG>, the in-vehicle apparatus includes an arithmetic processing device <NUM> including a pressing operation detection device according to this embodiment, a touch panel <NUM>, a display panel <NUM>, and a pressure detection sensor <NUM>.

The touch panel <NUM> corresponding to an operation unit according to an aspect of the invention detects a position touched by a user in a vehicle and outputs touch position information indicating the touched position. The display panel <NUM> displays an image generated by the arithmetic processing device <NUM> and is constituted by a liquid crystal panel or an organic electroluminescence (EL) panel, for example. The pressure detection sensor <NUM> detects pressure when the user presses the touch panel <NUM> and outputs pressing amount information indicating a pressing amount changed in accordance with the pressure.

As illustrated in <FIG>, the touch panel <NUM> is disposed on an uppermost layer, the display panel <NUM> is disposed on a layer beneath the touch panel <NUM>, and the pressure detection sensor <NUM> is disposed on a layer beneath the display panel <NUM>. When the user lightly touches a desired position on the touch panel <NUM>, the touch panel <NUM> detects the touched position. Furthermore, when the user strongly touches (presses) a desired position on the touch panel <NUM>, pressure of the touch is transmitted from the touch panel <NUM> through the display panel <NUM> to the pressure detection sensor <NUM> so that the touch panel <NUM> detects the touched position and the pressure detection sensor <NUM> detects the pressure (a pressing amount).

Note that configurations and arrangement of the touch panel <NUM>, the display panel <NUM>, and the pressure detection sensor <NUM> are merely examples and the present invention is not limited to these. For example, the display panel <NUM> may be configured slightly smaller than the touch panel <NUM> and the pressure detection sensor <NUM> and the touch panel <NUM> and the pressure detection sensor <NUM> are coupled to each other outside the display panel <NUM> so that pressure of pressing on the touch panel <NUM> performed by the user is directly transmitted from the touch panel <NUM> to the pressure detection sensor <NUM> without using the display panel <NUM>.

Information on the touched position detected by the touch panel <NUM> and information on the pressing amount detected by the pressure detection sensor <NUM> are supplied to the arithmetic processing device <NUM>. The arithmetic processing device <NUM> determines whether a pressing operation has been performed based on the touch position information supplied from the touch panel <NUM> and the pressing amount information supplied from the pressure detection sensor <NUM>, and executes a predetermined process in accordance with content of a GUI displayed in the touched position when determining that the pressing operation has been performed.

<FIG> is a block diagram illustrating an example of a functional configuration of an arithmetic processing device <NUM> including a pressing operation detection device according to an embodiment. As illustrated in <FIG>, the arithmetic processing device <NUM> according to this embodiment includes, as functional configurations thereof, a touch detection unit <NUM>, a pressing amount detection unit <NUM>, a pressing operation determination unit <NUM>, a determination controller <NUM>, a smoothing processor <NUM>, a touch time detection unit <NUM>, a processing execution unit <NUM>, and a display controller <NUM>. In these configurations, the touch detection unit <NUM>, the pressing amount detection unit <NUM>, the pressing operation determination unit <NUM>, the determination controller <NUM>, the smoothing processor <NUM>, and the touch time detection unit <NUM> constitute the pressing operation detection device according to this embodiment.

The functional blocks <NUM> to <NUM> may be configured by hardware, a digital signal processor (DSP), and/or software. When each of the functional blocks <NUM> to <NUM> is configured by software, each of the functional blocks <NUM> to <NUM> includes a central processing unit (CPU), a random access memory (RAM), and a read only memory (ROM) of a computer in practice and is realized when a program stored in a recording medium, such as the RAM, the ROM, a hard disk, or a semiconductor memory, is operated.

The touch detection unit <NUM> detects a touch on the touch panel <NUM> by the user based on touch position information supplied from the touch panel <NUM>. Furthermore, the touch detection unit <NUM> also detects a touched position on the touch panel <NUM> based on the touch position information supplied from the touch panel <NUM>. Information indicating that the touch panel <NUM> is touched or not touched is used by the pressing operation determination unit <NUM> and the touch time detection unit <NUM>, and information on the touched position is used by the processing execution unit <NUM>.

The pressing amount detection unit <NUM> successively detects amounts of pressing on the touch panel <NUM> performed by the user based on the pressing amount information supplied from the pressure detection sensor <NUM>. The information on the pressing amounts on the touch panel <NUM> is used by the pressing operation determination unit <NUM>.

The smoothing processor <NUM> performs a process of smoothing pressing amounts successively detected by the pressing amount detection unit <NUM>. The smoothing process is performed to remove noise which considerably changes a value of pressure detected by the pressure detection sensor <NUM> in an instantaneous manner, and is performed by an MAF, for example. Specifically, the smoothing processor <NUM> reduces an adverse effect of noise by performing a moving average process on the pressing amounts successively detected by the pressing amount detection unit <NUM>. Note that the MAF is an example of the smoothing process and the smoothing process is not limited to this. For example, a LPF process other than the MAF may be performed.

The touch time detection unit <NUM> detects an elapsed time in which a touch is continued from when the user start touching on the touch panel <NUM> (hereinafter referred to as a "touch time") based on the touch position information supplied from the touch panel <NUM>. Specifically, the touch time detection unit <NUM> has a timer function, starts a counting operation of a timer when supply of the touch position information is started by the touch panel <NUM>, and stops the counting operation of the timer when the supply of the touch position information from the touch panel <NUM> is terminated. A detected touch time is gradually increased in a period of time from the start of the counting operation of the timer to the termination of the counting operation of the timer.

The pressing operation determination unit <NUM> determines whether the pressing operation has been performed on the touch panel <NUM> based on a touch performed on the touch panel <NUM> detected by the touch detection unit <NUM> and an amount of pressing on the touch panel <NUM> detected by the pressing amount detection unit <NUM> or a pressing amount smoothed by the smoothing processor <NUM>. The term "pressing operation" includes, in addition to a light touch on the touch panel <NUM>, an operation of strongly pressing the touch panel <NUM> until a pressing amount set as a threshold value is reached. Specifically, the pressing operation determination unit <NUM> determines whether the pressing operation has been performed on the touch panel <NUM> based on a detection of a touch on the touch panel <NUM> performed by the touch detection unit <NUM> and a determination as to whether a pressing amount output from the pressing amount detection unit <NUM> or the smoothing processor <NUM> has reached the threshold value.

The determination controller <NUM> changes, in accordance with a touch time detected by the touch time detection unit <NUM>, content of a determination process to be performed by the pressing operation determination unit <NUM> such that a degree of easiness of a detection of a pressing operation when a pressing amount is instantaneously changed in a short period of time is differentiated. Specifically, the determination controller <NUM> changes content of the determination process to be performed by the pressing operation determination unit <NUM> such that, when a touch time detected by the touch time detection unit <NUM> is longer than a predetermined value (that is, when the counting operation performed by the timer is continued longer than a period of time indicated by the predetermined value), the determination as to whether the pressing operation has been performed is made using a pressing amount subjected to the smoothing process performed by the smoothing processor <NUM> whereas when the touch time is not longer than the predetermined value, the determination as to whether the pressing operation has been performed is made using a pressing amount detected by the pressing amount detection unit <NUM>.

Accordingly, when the touch time of touching on the touch panel <NUM> is longer than the predetermined value (that is, when a detection of a touch on the touch panel <NUM> by the touch detection unit <NUM> is continued until the touch time reaches the predetermined value), the pressing operation determination unit <NUM> determines whether the pressing operation has performed based on a result of a determination as to whether a pressing amount subjected to the smoothing process performed by the smoothing processor <NUM> reaches the threshold value. On the other hand, when the touch time of touching on the touch panel <NUM> is not longer than the predetermined value, it is determined whether the pressing operation has been performed based on a result of a determination as to whether a pressing amount detected by the pressing amount detection unit <NUM> reaches the threshold value.

Note that the pressing operation determination unit <NUM> determines whether a pressing operation has been performed using a pressing amount detected by the pressing amount detection unit <NUM> (a pressing amount which has not been smoothed by the smoothing processor <NUM>) in an initial state. When the touch time detected by the touch time detection unit <NUM> is longer than the predetermined value after a touch on the touch panel <NUM> is detected by the touch detection unit <NUM>, content of the determination process is changed such that the determination as to whether the pressing operation has been performed is made based on the pressing amount smoothed by the smoothing processor <NUM> under control of the determination controller <NUM>.

In general, a case where a touch on the touch panel <NUM> by the user is continued until the touch time reaches the predetermined value corresponds to a state in which the user performs a pressing operation such that pressure is gradually applied to the touch panel <NUM> for a comparatively long period of time. Therefore, in this case, the determination controller <NUM> controls the pressing operation determination unit <NUM> such that the determination as to whether a pressing operation has been performed is made using a pressing amount smoothed by the smoothing processor <NUM> so that a pressing operation is not easily detected in response to an instantaneous change of a pressing amount generated by noise.

On the other hand, a case where a touch on the touch panel <NUM> by the user is terminated before the touch time reaches the predetermined value corresponds to a state in which the user performs an operation of strongly pressing the touch panel <NUM> in a comparatively short period of time (a so-called tap operation). Therefore, in this case, the determination controller <NUM> controls the pressing operation determination unit <NUM> such that the pressing operation determination unit <NUM> determines whether a pressing operation has been performed using a pressing amount detected by the pressing amount detection unit <NUM> (a pressing amount which is not smoothed by the smoothing processor <NUM>) so that a pressing operation is easily detected when a pressing amount is instantaneously changed in a short period of time.

The predetermined value of the touch time to be used as a reference of the determination for changing the content of the determination process to be performed by the pressing operation determination unit <NUM> is appropriately set in advance based on information obtained as a trial in terms of an approximate standard value of a touch time from a start of a touch on the touch panel <NUM> to an end of the touch in the tap operation in which a pressing amount exceeds the threshold value in a short period of time.

When the pressing operation determination unit <NUM> determines that the pressing operation has been performed on the touch panel <NUM>, the processing execution unit <NUM> executes a predetermined process corresponding to a GUI displayed in a touched position on the touch panel <NUM>. The display controller <NUM> performs control such that an image generated by the processing execution unit <NUM> is displayed on the display panel <NUM> based on a result of the predetermined process performed by the processing execution unit <NUM>. By this, an image displayed on the display panel <NUM> is changed in accordance with the pressing operation performed on the touch panel <NUM>.

<FIG> are diagrams schematically illustrating an example of an operation of detecting a pressing operation performed by a pressing operation detection device according to an embodiment. <FIG> is a diagram illustrating an operation performed when a pressing operation is performed such that a touch time of touching on the touch panel <NUM> is longer than the predetermined value, and <FIG> is a diagram illustrating an operation performed when a pressing operation (a tap operation) is performed such that a touch time of touching on the touch panel <NUM> is shorter than the predetermined value. In <FIG>, axes of abscissae denote an elapsed time and axes of ordinates denote a pressing amount.

<FIG> is a diagram illustrating a state in which a touch on the touch panel <NUM> is started at a time point t1 and pressure is gradually increased. For simplicity of description, as indicated by a graph G1, it is assumed that the user increases pressure at a constant rate with time (a pressing amount is increased at a constant rate). A graph G2 schematically indicates a result of a moving average calculation performed by the smoothing processor <NUM> on pressing amounts successively detected by the pressing amount detection unit <NUM> as indicated by the graph G1.

In the example of <FIG>, a touch time of touching on the touch panel <NUM> counted from the time point t1 continues over a predetermined value Δt. While the user gradually increases the pressure on the touch panel <NUM> so that the pressing amount is gradually increased, noise is generated at time points t2 and t3. As illustrated in <FIG>, when a touch time of touching on the touch panel <NUM> is longer than the predetermined value Δt, the process of determining whether a pressing operation has been performed is made by the pressing operation determination unit <NUM> after the touch time exceeds the predetermined value Δt based on the graph G2 (the pressing amount smoothed by the smoothing processor <NUM>) instead of the graph G1 (the pressing amount detected by the pressing amount detection unit <NUM>). Therefore, even when a detection value of the pressing amount instantaneously becomes larger than the threshold value due to the second noise generated at the time point t3, the smoothed pressing amount does not exceeds the threshold value, and therefore, false determination of determining that the pressing operation has been performed at the time point t3 may be avoided.

Note that, while the user performs a pressing operation such that pressure applied on the touch panel <NUM> is gradually increased, before the touch time exceeds the predetermined value Δt, a process of determining whether a pressing operation has been performed is performed by the pressing operation determination unit <NUM> based on the pressing amount detected by the pressing amount detection unit <NUM> indicated by the graph G1. Here, even when noise is generated before the touch time exceeds the predetermined value Δt and the pressing amount detected by the pressing amount detection unit <NUM> is instantaneously changed, the pressing amount rarely exceeds the threshold value. Therefore, at a time point before the touch time exceeds the predetermined value Δt, an erroneous determination of a pressing operation due to noise is rarely performed.

On the other hand, <FIG> is a diagram illustrating a state in which a touch on the touch panel <NUM> is started at the time point t1, pressure is increased to exceed the threshold value in a short period of time, a peak is generated at a time point t4, the pressure is reduced, and the touch on the touch panel <NUM> is not detected at a time point t5. A graph G3 schematically indicates the series of changes in the pressing amount detected by the pressing amount detection unit <NUM>. A graph G4 schematically indicates a result of a moving average calculation performed by the smoothing processor <NUM> on pressing amounts successively detected by the pressing amount detection unit <NUM> as indicated by the graph G3.

In the example of <FIG>, a touch on the touch panel <NUM> is not detected before the touch time of the touching on the touch panel <NUM> counted from the time point t1 reaches the predetermined value. Therefore, the pressing operation determination process is performed by the pressing operation determination unit <NUM> based on the graph G3 (the pressing amount detected by the pressing amount detection unit <NUM>) instead of the graph G4 (the pressing amount smoothed by the smoothing processor <NUM>). Accordingly, even when the smoothed pressing amount does not exceed the threshold value, the pressing amount which is not smoothed exceeds the threshold value, and accordingly, a pressing operation (a tap operation) may be detected.

<FIG> is a flowchart of an example of an operation performed by a pressing operation detection device configured as described above. The flowchart illustrated in <FIG> is started when the in-vehicle apparatus is powered. Note that the pressing operation determination unit <NUM> is set so as to determine whether a pressing operation has been performed using a pressing amount detected by the pressing amount detection unit <NUM> in an initial state immediately after the power-on.

First, the touch detection unit <NUM> determines whether a touch on the touch panel <NUM> by the user is detected based on presence or absence of touch position information supplied from the touch panel <NUM> (step S1). When a touch on the touch panel <NUM> is not detected, the determination in step S1 is repeatedly performed. When a touch on the touch panel <NUM> is detected, the touch time detection unit <NUM> starts an operation of counting a touch time using a timer (step S2). Furthermore, the pressing amount detection unit <NUM> starts an operation of detecting an amount of pressing on the touch panel <NUM> (step S3).

Then the determination controller <NUM> determines whether the touch time detected by the touch time detection unit <NUM> is longer than the predetermined value (step S4). When the touch time is not longer than the predetermined value, the pressing operation determination unit <NUM> determines whether a pressing amount detected by the pressing amount detection unit <NUM> is larger than the threshold value (step S5). When the pressing amount is not larger than the threshold value, the process returns to step S4 and the operation of counting the touch time and the operation of detecting the pressing amount are continuously performed.

On the other hand, when the pressing operation determination unit <NUM> determines that the amount of pressing on the touch panel <NUM> is larger than the threshold value, the touch time detection unit <NUM> clears the timer (step S6) after stopping the operation of counting the touch time and the pressing operation determination unit <NUM> detects a pressing operation (step S7). In this case, the pressing operation determination unit <NUM> detects a tap operation performed such that a pressing amount reaches the threshold value in a period of time in which the touch time of the touching on the touch panel <NUM> is shorter than the predetermined value, and then, the process in the flowchart of <FIG> is terminated.

In step S4, when determining that the touch time of touching on the touch panel <NUM> is longer than the predetermined value, the determination controller <NUM> changes content of the determination process to be performed by the pressing operation determination unit <NUM> such that a determination as to whether a pressing operation has been performed is made using a pressing amount smoothed by the smoothing processor <NUM> (step S8). Furthermore, the touch time detection unit <NUM> stops the counting operation of the touch time and clears the timer (step S9).

Thereafter, the pressing operation determination unit <NUM> determines whether a pressing amount detected by the pressing amount detection unit <NUM> is larger than the threshold value (step S10). When the pressing operation determination unit <NUM> determines that the amount of pressing on the touch panel <NUM> is larger than the threshold value, the pressing operation determination unit <NUM> detects a pressing operation (step S7). In this case, the pressing operation determination unit <NUM> detects a pressing operation performed such that a pressing amount reaches the threshold value after the pressure on the touch panel <NUM> is gradually increased and the touch time exceeds the predetermined value, and the process of the flowchart in <FIG> is terminated in response to the detection.

On the other hand, when the pressing operation determination unit <NUM> determines that the amount of pressing on the touch panel <NUM> is not larger than the threshold value, the touch detection unit <NUM> determines whether the touch on the touch panel <NUM> is still detected (step S11). When the touch on the touch panel <NUM> is detected by the touch detection unit <NUM>, the process returns to step S10 where the operation of detecting a pressing amount is continuously performed. On the other hand, when the touch on the touch panel <NUM> is no longer detected by the touch detection unit <NUM>, the pressing operation determination unit <NUM> does not detect a pressing operation and the process of the flowchart in <FIG> is terminated.

As described above in detail, when the determination as to whether a pressing operation has been performed on the touch panel <NUM> is made based on a touch on the touch panel <NUM> performed by the user and a pressing amount, the content of the determination process based on the pressing amount to be performed by the pressing operation determination unit <NUM> is changed such that a degree of easiness of a detection of a pressing operation when a pressing amount is instantaneously changed in a short period of time is differentiated (a determination process based on a pressing amount detected by the pressing amount detection unit <NUM> or a determination process based on a pressing amount smoothed by the smoothing processor <NUM>).

With such configuration, when a pressing operation is performed such that pressure is gradually increased for a comparatively long time, the determination process based on a pressing amount smoothed by the smoothing processor <NUM> is performed, so that false detection of a pressing operation caused by an instantaneous change of a pressing amount due to noise may be avoided. Furthermore, since the determination process is performed based on a pressing amount detected by the pressing amount detection unit <NUM> when a pressing operation is performed such that a strong press is performed in a comparatively short period of time, a miss of detection of a pressing operation may be avoided.

Note that the content of the control performed by the determination controller <NUM> described in the foregoing embodiments is merely an example and the present invention is not limited to this. For example, the determination controller <NUM> sets a first threshold value to the pressing operation determination unit <NUM> when the touch time detected by the touch time detection unit <NUM> is longer than the predetermined value and sets a second threshold value smaller than the first threshold value to the pressing operation determination unit <NUM> when the touch time is not longer than the predetermined value, so that content of the determination process to be performed by the pressing operation determination unit <NUM> is changed.

In this case, the pressing operation determination unit <NUM> performs a determination process based on a pressing amount smoothed by the smoothing processor <NUM> when either of the threshold values is used. Specifically, the pressing operation determination unit <NUM> determines whether a pressing operation has been performed based on a result of a determination as to whether a pressing amount smoothed by the smoothing processor <NUM> reaches the first threshold value when a touch time of touching on the touch panel <NUM> is longer than the predetermined value. On the other hand, when the touch time of touching on the touch panel <NUM> is not longer than the predetermined value, the pressing operation determination unit <NUM> determines whether a pressing operation has been performed based on a result of a determination as to whether a pressing amount smoothed by the smoothing processor <NUM> reaches the second threshold value.

Here, the pressing operation determination unit <NUM> determines whether a pressing operation has been performed using the second threshold value in the initial state. When the touch time detected by the touch time detection unit <NUM> is longer than the predetermined value after a touch on the touch panel <NUM> is detected by the touch detection unit <NUM>, content of the determination process is changed such that the pressing operation is determined using the first threshold value instead of the second threshold value under control of the determination controller <NUM>.

<FIG> are diagrams schematically illustrating an example of an operation of detecting a pressing operation when a threshold value of the pressing operation determination unit <NUM> is changed. <FIG> is a diagram illustrating an operation performed when a pressing operation is performed such that a touch time of touching on the touch panel <NUM> is longer than the predetermined value, and <FIG> is a diagram illustrating an operation performed when a pressing operation (a tap operation) is performed such that a touch time of touching on the touch panel <NUM> is shorter than the predetermined value. The first threshold value illustrated in <FIG> is equal to the threshold value illustrated in the example of <FIG>. Therefore, the operation illustrated in <FIG> is the same as the operation content illustrated in <FIG>.

In <FIG>, a graph G3 indicating a change of a pressing amount detected by the pressing amount detection unit <NUM> and a graph G4 indicating a change of a pressing amount smoothed by the smoothing processor <NUM> are the same as those illustrated in <FIG>. <FIG> is different from <FIG> in a second threshold value which is smaller than a first threshold value. In the example of <FIG>, the pressing operation determination unit <NUM> determines whether a pressing operation has been performed based on a result of a determination as to whether a pressing amount detected by the pressing amount detection unit <NUM> is larger than the first threshold value as indicated by the graph G3.

On the other hand, in the example of <FIG>, the pressing operation determination unit <NUM> determines whether a pressing operation has been performed based on a result of a determination as to whether a pressing amount smoothed by the smoothing processor <NUM> is larger than the second threshold value as indicated by the graph G4. In this case, the pressing amount smoothed by the smoothing processor <NUM> does not exceed the first threshold value but exceeds the second threshold value, and therefore, a pressing operation (a tap operation) may be detected.

Note that the pressing operation determination unit <NUM> may determine whether a pressing operation has been performed based on a result of a determination as to whether a pressing amount smoothed by the smoothing processor <NUM> reaches the first threshold value when the touch time of touching on the touch panel <NUM> is longer than the predetermined value, and on the other hand, the pressing operation determination unit <NUM> may determine whether a pressing operation has been performed based on a result of a determination as to whether a pressing amount detected by the pressing amount detection unit <NUM> (a pressing amount not smoothed by the smoothing processor <NUM>) reaches the second threshold value when the touch time of touching on the touch panel <NUM> is not longer than the threshold value. Note that it is possible that a pressing amount which is instantaneously increased due to noise exceeds the second threshold value, and therefore, a pressing amount smoothed by the smoothing processor <NUM> is preferably used.

Although the touch panel <NUM> is used as an example of an operation unit in the foregoing embodiment, the present invention is not limited to this. For example, a button of hardware which is mechanically configured may be used as the operation unit.

Furthermore, although the threshold values (the first and second threshold values) used for the determination as to whether a pressing operation has been performed are absolute values in the foregoing embodiment, the present invention is not limited to this. For example, in a case where a pressing detection structure including the touch panel <NUM> and the pressure detection sensor <NUM> is mounted on a vehicle, depending on arrangement of the pressing detection structure disposed on a dashboard or the like, the pressure detection sensor <NUM> may detect pressure due to vibration of the vehicle or the pressure detection sensor <NUM> may detect pressure when the user presses a surrounding portion of the touch panel <NUM> except for the touch panel <NUM>. Specifically, the pressure detection sensor <NUM> may detect pressure although the touch panel <NUM> does not detect a touch. In this case, pressure (a pressing amount) detected by the pressure detection sensor <NUM> when the touch panel <NUM> does not detect a touch is used as a reference and a relative value relative to the reference may be set as a threshold value.

Claim 1:
A pressing operation detection device including a touch detection unit (<NUM>) configured for detecting a touch on an operation unit (<NUM>) performed by a user and a pressing amount detection unit (<NUM>) configured for detecting a pressing amount of pressing on the operation unit performed by the user, the pressing operation detection device further comprising:
a smoothing processing unit (<NUM>) configured to perform a smoothing process on pressing amounts successively detected by the pressing amount detection unit (<NUM>);
a pressing operation determination unit (<NUM>) configured to determine whether a pressing operation has been performed on the operation unit (<NUM>) based on a touch on the operation unit and a pressing amount;
a touch time detection unit (<NUM>) configured to detect a touch time which is an elapsed time in which a touch on the operation unit (<NUM>) by the user is continued from start of the touch (t1); and
a determination controller (<NUM>) configured to change content of the determination process to be performed by the pressing operation determination unit (<NUM>) such that the determination as to whether a pressing operation has been performed is made using a pressing amount smoothed by the smoothing processing unit (<NUM>) when the touch time detected by the touch time detection unit (<NUM>) is longer than a predetermined value (Δt) whereas the determination as to whether a pressing operation has been performed is made using a pressing amount detected by the pressing amount detection unit (<NUM>) when the touch time is not longer than the predetermined value (Δt),
wherein the pressing operation determination unit (<NUM>) is configured to determine whether a pressing operation has been performed based on a result of a determination as to whether a pressing amount smoothed by the smoothing processing unit (<NUM>) reaches a threshold value when the touch time is longer than the predetermined value (Δt) whereas the pressing operation determination unit (<NUM>) is configured to determine whether a pressing operation has been performed based on a result of a determination as to whether a pressing amount detected by the pressing amount detection unit (<NUM>) reaches the threshold value when the touch time is not longer than the predetermined value (Δt).