Patent Description:
In recent years, input devices such as touchpads allowing operators to perform touch operations by touching operation surfaces have been widely used. Unlike the case of a switch device and a variable resistor, the operator is unable to feel a tactile sensation when operating such an input device. In light of the above, an input device capable of providing vibration feedback has been proposed. The input device provides an operation sensation by applying a vibration to an operation surface in response to a touch operation.

For example, Patent Document <NUM> describes a tactile sensation-providing apparatus that applies a pressure to an operator's finger by causing an operation surface to vibrate based on a plurality of waveform patterns.

<CIT> discloses a haptic output device including an actuator configured to generate a haptic effect, and a processor configured to communicate a driving signal to the actuator and to communicate a braking signal to the actuator before or at the same time the driving signal is terminated to generate the haptic effect.

<CIT> discloses a haptic actuator or a device having a haptic actuator that is capable of producing short, sharp and crisp pulses in a short amount of time.

However, tactile sensations provided by the tactile sensation-providing apparatus described in Patent Document <NUM> are limited to one type of tactile sensation.

It is an object of the present disclosure to provide an input device, a control method, and a program capable of providing a plurality of types of tactile sensations.

The invention is defined by the independent claims and various embodiments are disclosed in the dependent claims.

According to the present disclosure, a plurality of types of tactile sensations can be provided.

The inventor has made earnest investigations such that one input device can produce operation sensations of a plurality of types of tactile switches. As a result, the inventor has found that an operation sensation of a tactile switch depends on the duration of a period of vibration, generated by the tactile switch, during which the amplitude of the vibration becomes maximum (hereinafter may be referred to as a "maximum vibration period"). Accordingly, operation sensations of a plurality of tactile switches can be produced by appropriately controlling the maximum vibration period of vibration applied to an operator.

In an input device that includes a spring-mass system, the spring-mass system vibrates at a natural resonance frequency. Therefore, it would not be easy to control the duration of the maximum vibration period of vibration.

In the following, vibrations generated by an input device will be described with reference to a reference example.

<FIG> is a schematic diagram illustrating an input device according to a reference example. <FIG> is a timing diagram illustrating a first example of the operation of the input device.

As illustrated in <FIG>, an input device <NUM> according to the reference example includes a movable part <NUM>, a piezoelectric actuator <NUM>, elastic support parts <NUM>, and a housing <NUM> that is structurally rigid. The movable part <NUM> driven by the piezoelectric actuator <NUM> is supported by the elastic support parts <NUM> within the housing <NUM>. For example, the movable part <NUM> includes a touchpad and a decorative panel. The movable part <NUM> and the elastic support parts <NUM> constitute a spring-mass system. Further, a voltage rising at time t11 and falling at time t12 is applied, as a control signal, to the piezoelectric actuator <NUM>.

As illustrated in <FIG>, when the voltage applied to the piezoelectric actuator <NUM> rises (at the time t11), the movable part <NUM> is driven by the piezoelectric actuator <NUM>. At this time, a first vibration v1 is started and the movable part <NUM> is moved from initial position p0 to position p1. The neutral position of the first vibration v1 is the position p1. The frequency of the first vibration v1 is a resonance frequency f0 of the spring-mass system determined by the spring constant of the elastic support parts <NUM> and the mass of the movable part <NUM>. The first vibration v1 attenuates over time.

Thereafter, when the voltage applied to the piezoelectric actuator <NUM> falls (at the time t12), a second vibration v2 is started and the movable part <NUM> is moved from the position p1 to the position p0. The neutral position of the second vibration v2 is the position p0. The frequency of the second vibration v2 is also the resonance frequency f0, and the second vibration v2 attenuates over time.

As illustrated in <FIG>, if a period of time from the start of the first vibration v1 to the convergence of the first vibration v1 is longer than a period of time Δt10 from the time t11 to the time t12, the first vibration v1 and the second vibration v2 are independent of each other.

Conversely, if the period of time from the start of the first vibration v1 to the convergence of the first vibration v1 is shorter than the period of time Δt10, the second vibration v2 interferes with the first vibration v1. In this case, as of the time t12, the vibration of the movable part <NUM> becomes a vibration in which the first vibration v1 and the second vibration v2 are combined (a combined vibration). As used herein, the "combined vibration" includes not only a combined vibration of which the first vibration v1 and the second vibration v2 after the start of the second vibration v2, but also a combined vibration of the first vibration v1 and the second vibration v2 with an amplitude of zero before the start of the second vibration v2. Therefore, the "combined vibration" includes a vibration between the time t11 and the time t12 before the start of the second vibration v2. Further, the "combined vibration" includes the first vibration v1 and the second vibration v2 that are independent of each other as illustrated in <FIG>.

Specifically, if the period of time Δt10 is less than or equal to one half of a period of the first vibration v1, the first period of a combined vibration v12 becomes shorter than the period of the first vibration v1. This means that a duration Δt20 of the first period of the combined vibration v12 can be adjusted by controlling the period of time Δt10, thereby allowing multiple types of operation sensations of tactile switches to be provided.

For example, <FIG> and <FIG> depict vibration characteristics of four tactile switches configured to produce operation sensations. The duration of the maximum vibration period of a tactile switch SW1 exhibiting vibration characteristics illustrated in <FIG> is denoted as Δt1, the duration of the maximum vibration period of a tactile switch SW2 exhibiting vibration characteristics illustrated in <FIG> is denoted as Δt2, the duration of the maximum vibration period of a tactile switch SW3 exhibiting vibration characteristics illustrated in <FIG> is denoted as Δt3, and the duration of the maximum vibration period of a tactile switch SW4 exhibiting vibration characteristics illustrated in <FIG> is denoted as Δt4.

In order for the four tactile switches SW1 through SW4 to produce operation sensations, the period of time Δt10 may be controlled in the piezoelectric actuator <NUM>. That is, the period of time Δt10 may be controlled such that the duration Δt20 of the first period of the combined vibration v12 substantially matches each of the durations Δt1 through Δt4 of the tactile switches SW1 through SW4. In this manner, the input device <NUM> can produce operation sensations of the tactile switches SW1 through SW4.

Further, the maximum sensitivity of sensory organs in the fingers of humans is around <NUM>. If a vibration with a frequency of approximately <NUM> is applied, humans tend to feel a sharp operation sensation (clicking sensation). Conversely, if a vibration with a frequency of approximately <NUM> is applied, humans tend to feel a soft operation sensation. As the frequency becomes lower than <NUM>, it becomes difficult to feel an operation sensation. Further, humans can also perceive vibrations of approximately <NUM>. For this reason, the frequency in the first period of the combined vibration generated by the input device <NUM> is preferably <NUM> to <NUM>, and is more preferably <NUM> to <NUM>.

Further, preferably, the vibration of the spring-mass system is not readily perceived such that operation sensations imparted by the combined vibration v12 can be distinguished from the sensation of vibration of the spring-mass system. Accordingly, the resonance frequency of the vibration of the spring-mass system included in the input device <NUM> is preferably less than or equal to <NUM>, and is more preferably less than or equal to <NUM>. In addition, the frequency in the first period of the combined vibration v12 is preferably greater than or equal to the resonance frequency of the spring-mass system.

Further, the frequency in the first period of the combined vibration v12 may be similar to the resonance frequency of the spring-mass system so as to provide the softest operation sensation, among operation sensations produced by the input device <NUM>. In this case, the softest operation sensation can be provided at the resonance frequency of the spring-mass system.

In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the specification and drawings, elements having substantially the same functions or configurations are referred to by the same reference numerals, and a duplicate description thereof may be omitted.

An input device including a piezoelectric actuator, which is an example of an actuator, will be described. <FIG> is a perspective view of an input device according to an embodiment. <FIG> is a top view of the input device according to the embodiment. <FIG> are cross-sectional views of the input device according to the embodiment. <FIG> corresponds to a cross-sectional view taken through I-I of <FIG>. <FIG> corresponds to a cross-sectional view taken through II-II of <FIG>.

As illustrated in <FIG>, an input device <NUM> according to an embodiment includes a fixed base <NUM>, a bezel <NUM> fixed on the periphery of the fixed base <NUM>, and a decorative panel <NUM> located inside the bezel <NUM>. A touchpad <NUM> is disposed on the fixed base <NUM> side of the decorative panel <NUM>. A movable base <NUM> is disposed on the fixed base <NUM> side of the touchpad <NUM>. The movable base <NUM> includes a flat plate part <NUM> wider than both the touchpad <NUM> and the decorative panel <NUM> in planar view, and includes a wall part <NUM> extending from the perimeter edge of the flat plate part <NUM> toward the fixed base <NUM>. The fixed base <NUM> has a protrusion <NUM> at the center in planar view, and an actuator <NUM> is disposed on the protrusion <NUM>. The actuator <NUM> may be a piezoelectric actuator, and contacts the protrusion <NUM> and the flat plate part <NUM>. The touchpad <NUM> is an example of a touchpad, the movable base <NUM> is an example of a holder that holds the touchpad <NUM>. The touchpad <NUM> and the movable base <NUM> are included in an operation panel member. The operation panel member is an example of an operation part. The fixed base <NUM> is an example of a support member.

A plurality of rubber components <NUM> are disposed between the wall part <NUM> and the fixed base <NUM> and are in contact with the wall part <NUM> and the fixed base <NUM>. The rubber components <NUM> are arranged at least at positions of apexes of a triangle in planar view. For example, the rubber components <NUM> are arranged around each of the four corners of the touchpad <NUM> in planar view.

A plurality of rubber components <NUM> are disposed between the flat plate part <NUM> and the bezel <NUM> and are in contact with the flat plate part <NUM> and the bezel <NUM>. The rubber components <NUM> are arranged at least at positions of apexes of a triangle in planar view. For example, the rubber components <NUM> are arranged around each of the four corners of the touchpad <NUM> so as to overlap the rubber components <NUM> in planar view. The rubber components <NUM> and <NUM> are examples of an elastic member.

A plurality of rubber components <NUM> are disposed between the protrusion <NUM> and the flat plate part <NUM> and are in contact with the protrusion <NUM> and the flat plate part <NUM>. The rubber components <NUM> are arranged at least at positions of apexes of a triangle around the actuator <NUM> in planar view. For example, the rubber components <NUM> are arranged at three respective positions between the actuator <NUM> and each of the four sides of the touchpad <NUM> (at positions closer to the center of the touchpad <NUM> in planar view than are the rubber components <NUM> and the rubber components <NUM>).

For example, the rubber components <NUM> are harder than the rubber components <NUM> and the rubber components <NUM>. The rubber components <NUM> and the rubber components <NUM> have substantially the same hardness. The rubber components <NUM> and the rubber components <NUM> are examples of a first elastic member, and the rubber components <NUM> are examples of a second elastic member. The flat plate part <NUM> is supported via the elastic members such that a touch surface of the touchpad <NUM> is tiltable.

Further, a plurality of photo interrupters <NUM>, <NUM>, <NUM>, and <NUM> are disposed on the fixed base <NUM>. The photo interrupters <NUM> through <NUM> are able to emit light to points 171A through 174A and receive light reflected from the flat plate part <NUM>. The points 171A through 174A are located on the flat plate part <NUM> of the movable base <NUM> and above the photo interrupters <NUM> through <NUM>. Accordingly, the photo interrupters <NUM>, <NUM>, <NUM>, and <NUM> can detect the distances to the points of the flat plate part <NUM> to which light is emitted. For example, the photo interrupters <NUM> through <NUM> are disposed inward relative to the four corners of the touchpad <NUM> in planar view. The photo interrupters <NUM> through <NUM> are arranged at least at positions of apexes of a triangle in planar view. The photo interrupters <NUM> through <NUM> are examples of first through fourth sensors (photosensors). The first through fourth sensors (photosensors) are examples of a sensor. A surface <NUM> of the fixed base <NUM> on which the photo interrupters <NUM> through <NUM> are disposed is an example of a reference plane. The reference plane is spaced apart from the operation panel member (that includes the movable base <NUM> and the like). In the present embodiment, the reference plane is designated as a reference plane containing the X axis and the Y axis, and a direction perpendicular to the reference plane is designated as a Z-axis direction (a first direction).

Further, a signal processing unit <NUM> is disposed on the fixed base <NUM>. The signal processing unit <NUM> performs a process as will be described later to drive the actuator <NUM> in response to a touch operation on the touchpad <NUM>, thereby providing tactile feedback to a user. The signal processing unit <NUM> may be a semiconductor chip, for example. In the present embodiment, the signal processing unit <NUM> is disposed on the fixed base <NUM>; however, the position of the signal processing unit <NUM> is not limited thereto, and the signal processing unit <NUM> may be provided between the touchpad <NUM> and the movable base <NUM>, for example. The signal processing unit <NUM> is an example of a controller.

As an example operation of the input device <NUM> configured as described above, the actuator <NUM> vibrates in the direction perpendicular to the touch surface of the touchpad <NUM> in response to a touch operation on the touchpad <NUM> in accordance with the position and load of the touch operation. By feeling the vibration on the touch surface, the user is able to recognize what response is given to his/her touch operation performed on the input device <NUM>, without visually checking a display device of the input device <NUM> or the like. For example, if the input device <NUM> is provided in the center console of an automobile for use as various switches, a driver is able to recognize what response is given to his/her touch operation based on the vibration of the actuator <NUM>, without turning his/her eyes to the input device <NUM>. Note that the actuator <NUM> is not limited to the above-described example, and may be configured to generate a vibration in any direction.

Next, the basic concept of a process for detecting a load applied to the touchpad <NUM> according to the present embodiment will be described. In the present embodiment, the distance to the flat plate part <NUM> detected by each of the photo interrupters <NUM> through <NUM> and the coordinates of a touched position detected by the touchpad <NUM> are used to derive an equation of a plane regarding the flat plate part <NUM>, that is, an equation of the plane containing the points 171A through 174A, followed by obtaining a displacement at the touched position.

In the following, an equation of a plane will be described. <FIG> is a drawing illustrating an XYZ coordinate system. In the XYZ coordinate system, there are three points. The three points are a point a (xa, ya, za), a point b (xb, yb, zb), and a point c (xc, yc, zc). In this case, the components (x<NUM>, y<NUM>, z<NUM>) of a vector ac (hereinafter may be referred to as "Vac") are (xc - xa, yc - ya, zc - za), and the components (x<NUM>, y<NUM>, z<NUM>) of a vector ab (hereinafter may be referred to as "Vab") are (xb - xa, yb - ya, zb - za). Accordingly, the cross product (Vac · Vab) is (y<NUM>z<NUM> - z<NUM>y<NUM>, z<NUM>x<NUM> - x<NUM>z<NUM>, x<NUM>y<NUM> - y<NUM>x<NUM>). This cross product corresponds to a normal vector of a plane containing the point a, the point b, and the point c. When (y<NUM>z<NUM> - z<NUM>y<NUM>, z<NUM>x<NUM> - x<NUM>z<NUM>, x<NUM>y<NUM> - y<NUM>x<NUM>) is designated as (p, q, r), an equation of the plane containing the point a, the point b, and the point c is represented by the following equation (<NUM>).

The equation (<NUM>), which is a general formula, may be simplified by using, as an XYZ coordinate system, an orthogonal coordinate system in which the X coordinate and Y coordinate of the point a are zero. <FIG> is a diagram illustrating positional relationships in an XYZ orthogonal coordinate system. As illustrated in <FIG>, in this XYZ orthogonal coordinate system, there are four points on a plane <NUM>. The four points are a point a (<NUM>,<NUM>,za), a point b (xb, <NUM>, zb), a point c (<NUM>, yc, zc), and a point d (xb, yc, zd). The coordinates of the point a, the point b, and the point c are related as follows. <MAT> <MAT> <MAT>.

As a result, an equation of the plane <NUM> containing the point a, the point b, and the point c is represented by the following equation (<NUM>).

Then, the equation (<NUM>) can be represented as an equation (<NUM>) as follows.

Accordingly, the Z coordinates of the three points on the plane <NUM> may be identified by the first sensor, the second sensor, and the third sensor, and the X coordinate and the Y coordinate of the touched position on the plane <NUM> may be identified by the touchpad. Then, the Z coordinate of the touched position can be identified. Further, a displacement in the Z-axis direction at the touched position may be obtained from a change in the Z coordinate occurring upon the touch operation.

In the present embodiment, the X coordinate and Y coordinate of the touched position on the touchpad <NUM> can be obtained by the touchpad <NUM>. Namely, when contact is made to a point e in <FIG>, an X coordinate (x) and a Y coordinate (y) of the point e can be derived from the outputs of the touchpad <NUM>. Further, photo interrupters corresponding to the point a, the point b, and the point c may be arranged as the first sensor, the second sensor, and the third sensor, respectively, and the X coordinate (xb) of the point b and the Y coordinate (yc) of the point c may be obtained in advance. Then, the outputs of the photo interrupters may be used to detect the distances to the flat plate part <NUM> to obtain the Z coordinates (za, zb, zc) of these respective points, followed by calculating the Z coordinate (z) of the point e from the equation (<NUM>).

Namely, in the initial state, the plane <NUM> of the touchpad <NUM> and a plane containing the three photo interrupters arranged at the positions corresponding to the point a, the point b, and the point c may be parallel to each other. The coordinates of the point e may then be obtained after the flat plate part <NUM> and the touchpad <NUM> tilt upon pressure applied to the touchpad <NUM>. Accordingly, a displacement in the Z-axis direction at the point e occurring upon the application of pressure can be obtained. Even if the plane <NUM> and the plane containing the three photo interrupters are not parallel to each other in the initial state, a displacement in the Z-axis direction at the point e in response to the application of pressure can be obtained by a similar calculation.

Further, a displacement in the Z-axis direction at the point e in response to a touch operation may be used to determine whether a load exerted on the point e exceeds a predetermined reference value, and tactile feedback can be controlled based on the determination result. Namely, the relationships between loads exerted on a plurality of points on the plane <NUM> and displacements in the Z-axis direction may be obtained in advance. Then, it is determined whether the displacement in the Z-axis direction obtained through the above-described method exceeds a threshold value corresponding to the reference value, followed by controlling tactile feedback. <FIG> is a diagram illustrating example relationships between applied loads and displacements in the Z-axis direction.

As illustrated in <FIG>, touch operations are performed at <NUM> measurement grid points <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, with loads of <NUM> gf (<NUM> N), <NUM> gf (<NUM> N), <NUM> gf (<NUM> N), and <NUM> gf (<NUM> N) as illustrated in <FIG>. Further, tactile feedback is given when a load exceeding <NUM> gf (<NUM> N), which is used as a reference value, is applied. Note that because the actuator <NUM> and the like are provided under the movable base <NUM>, displacements differ depending on the position of measurement.

When a touch operation is performed at any of the measurement points <NUM> through <NUM>, it can be determined whether the applied load exceeds the reference value based on the relationships illustrated in <FIG>. Namely, if a displacement in the Z-axis direction as calculated from the equation (<NUM>) exceeds the displacement corresponding to <NUM> gf (<NUM> N) indicated in <FIG>, it is determined that the applied load exceeds the reference value. In a case where a touch operation is performed at the measurement point <NUM>, for example, a displacement threshold value is <NUM>. In this case, if a displacement exceeds <NUM>, it is determined that the applied load reaches the reference value for generating tactile feedback.

If a touch operation is performed at a position different from the measurement points <NUM> through <NUM>, it can be determined whether the applied load exceeds the reference value by using displacement thresholds at the measurement points around such a position. <FIG> and <FIG> are diagrams illustrating an example method of determining a load. As illustrated in <FIG>, a touch operation is assumed to be performed at a point <NUM> inside the rectangle defined by the measurement points <NUM>, <NUM>, <NUM>, and <NUM>. In this case, as illustrated in <FIG>, a displacement threshold at a point <NUM> which has the same Y coordinate as the point <NUM> between the two measurement points <NUM> and <NUM> aligned in the X-axis direction is calculated through linear interpolation from the respective thresholds of the measurement points <NUM> and <NUM>. Similarly, as illustrated in <FIG>, a displacement threshold at a point <NUM> which has the same Y coordinate as the point <NUM> between the two measurement points <NUM> and <NUM> aligned in the X-axis direction is calculated through linear interpolation from the respective threshold values of the measurement points <NUM> and <NUM>. Further, as illustrated in <FIG>, the threshold at the point <NUM> is calculated through linear interpolation from the respective threshold values of the points <NUM> and <NUM>. Separately from the above, a displacement in the Z-axis direction at the point <NUM> can be calculated by the above-described equation (<NUM>). By comparing these values, it can be determined whether the load applied to the point <NUM> different from the measurement points <NUM> through <NUM> exceeds the reference value.

Based on the above-described basic concept, the signal processing unit <NUM> determines whether a load applied to a touched position on the touchpad <NUM> exceeds the reference value for generating tactile feedback. If the reference value is exceeded, the signal processing unit <NUM> activates the actuator <NUM> to generate tactile feedback. <FIG> is a diagram illustrating a configuration of the signal processing unit <NUM>.

The signal processing unit <NUM> includes a CPU (central processing unit) <NUM>, a ROM (read-only memory) <NUM>, a RAM (random-access memory) <NUM>, and an auxiliary storage unit <NUM>. The CPU <NUM>, the ROM <NUM>, the RAM <NUM>, and the auxiliary storage unit <NUM> constitute a computer. The components of the signal processing unit <NUM> are connected to one another through a bus <NUM>.

The CPU <NUM> executes various types of programs (such as a load determination program) stored in the auxiliary storage unit <NUM>.

The ROM <NUM> is a nonvolatile main memory device. The ROM <NUM> stores various programs, data, and the like necessary for the CPU <NUM> to execute the various types of programs stored in the auxiliary storage unit <NUM>. Specifically, the ROM <NUM> stores boot programs such as Basic Input/Output System (BIOS) and Extensible Firmware Interface (EFI).

The RAM <NUM> is a volatile main memory device such as a dynamic random-access memory (DRAM) and a static random-access memory (SRAM). The RAM <NUM> serves as a work area to which the various types of programs stored in the auxiliary storage unit <NUM> are loaded when executed by the CPU <NUM>.

The auxiliary storage unit <NUM> is an auxiliary storage device for storing the various types of programs executed by the CPU <NUM> and various data generated by the CPU <NUM> executing the various types of programs.

The signal processing unit <NUM> having the hardware configuration as described above performs a process as described below. <FIG> is a flowchart illustrating a process performed by the signal processing unit <NUM>.

First, the signal processing unit <NUM> detects the touchpad <NUM> (step S1). Then, the signal processing unit <NUM> determines whether a user's finger is in contact with the touchpad <NUM> (step S2). If the signal processing unit <NUM> determines that a user's finger is not in contact with the touchpad <NUM>, the drifts of the photo interrupters <NUM> through <NUM> are canceled (step S3).

Conversely, if the signal processing unit <NUM> determines that a user's finger is in contact in contact with the touchpad <NUM>, the signal processing unit <NUM> acquires respective detection signals from the photo interrupters <NUM> through <NUM> (step S4). For example, if the signals output from the photo interrupters <NUM> through <NUM> are analog signals, the signal processing unit <NUM> acquires the signals that have been converted into digital signals.

Next, the detection signals of the photo interrupters <NUM> through <NUM> are used to calculate displacements Z<NUM> through Z<NUM> in the Z-axis direction at respective detection points on the flat plate part <NUM> (step S5).

Thereafter, one triangle is selected as a representative triangle from a plurality of triangles defined by three of the four photo interrupters <NUM> through <NUM> (step S6). Preferably, the representative triangle may be a triangle that contains therein the touched position on the touchpad <NUM>. In the example of <FIG>, if the point e is touched, a triangle acd or a triangle acb may preferably be used. This is because the shorter the distance between the touched position and the photo interrupters <NUM> through <NUM> is, the higher the accuracy is.

Next, a displacement Z in the Z-axis direction at the touched position on the touchpad <NUM> is calculated (step S7). Namely, the equation (<NUM>) is used to calculate the displacement Z in the Z-axis direction at the touched position based on the X coordinate and Y coordinate of the touched position detected by the touchpad <NUM> and the displacements in the Z-axis direction calculated from the detection signals of the three photo interrupters selected as constituting the representative triangle in step S6.

Further, the relationships between applied loads and displacements in the Z-axis direction, which are obtained in advance as in the example illustrated in <FIG> and stored in the ROM <NUM>, are retrieved, and then a threshold Zth (an ON threshold Zth) in the Z-axis direction at the touched position is calculated (step S8).

Then, it is determined whether the displacement Z exceeds the ON threshold Zth (step S9). If the ON threshold Zth is exceeded, the applied load is regarded as exceeding the reference value. In this case, the actuator <NUM> is activated to provide tactile feedback (step S10).

In this manner, the input device <NUM> according to the present embodiment provides tactile feedback. The photo interrupters <NUM> through <NUM> are able to detect the Z coordinates of the points 171A through 174A on the flat plate part <NUM> with high accuracy, and the touchpad <NUM> is able to detect the X coordinate and Y coordinate of the touched position with high accuracy. As a result, the above-described process allows the Z coordinate of the touched position to be also detected with high accuracy. Even when the ON threshold Zth is a small value of several tens of micrometers, whether or not to provide tactile feedback can be determined with high accuracy.

The rubber components <NUM> disposed around the actuator <NUM> are preferably harder than the rubber components <NUM> and rubber components <NUM> disposed in the vicinity of the peripheral edge of the movable base <NUM>. The rubber components <NUM> and the rubber components <NUM> support the movable base <NUM> between the fixed base <NUM> and the bezel <NUM> to the extent to which the actuator <NUM> is able to vibrate the movable base <NUM>. If the hardness of the rubber components <NUM> and the rubber components <NUM> were excessively high, it would be difficult to make a user feel a vibration upon the activation of the actuator <NUM>. Conversely, the easier it is for the movable base <NUM> to tilt in response to a touch operation, the more likely it is for the displacements Z1 through Z4 in the Z-axis direction by the photo interrupters <NUM> through <NUM> to increase, and the more likely it is for error to be reduced. Further, the harder the rubber components <NUM> are, the greater the repulsive force to a user is. Accordingly, the rubber components <NUM> are preferably harder than the rubber components <NUM> and the rubber components <NUM>.

<FIG> is a schematic diagram illustrating the tilt of the movable base. As illustrated in <FIG>, an operation panel member <NUM>, which includes the movable base <NUM> and the touchpad <NUM>, is provided with rubber components <NUM> at the perimeter thereof, and is provided with a rubber component <NUM> at the center thereof. The rubber components <NUM> corresponds to the rubber components <NUM> and the rubber components <NUM>, and the rubber component <NUM> correspond to the rubber components <NUM>. In this case, pressing the operation panel member <NUM> with a finger <NUM> at a position near the perimeter thereof causes a rubber component <NUM> situated near the perimeter of the operation panel member <NUM> to be compressed to a large extent, while the rubber component <NUM> is hardly compressed. Further, the operation panel member <NUM> is lifted above the rubber component <NUM>. As a result, large displacements of the operation panel member <NUM> are observed near both of the rubber components <NUM>. If the hardness of the rubber component <NUM> were comparable with the hardness of the rubber components <NUM>, all of the rubber component <NUM> and the rubber components <NUM> would be compressed with only small differences therebetween. As a result, relatively small displacements of the operation panel member <NUM> would be observed near both of the rubber components <NUM>. Note that the actuator <NUM> of the input device <NUM> also serves as part of the rubber component <NUM> of <FIG> to provide a fulcrum point.

Further, in the above-described process, one representative triangle is identified, a displacement at a touched position is calculated, and, a determination is made based on the displacement. Alternatively, two or more representative triangles may be identified, displacements (such as a first displacement and a second displacement) may be calculated for the respective representative triangles, the average value of these displacements may be obtained, and a determination may be made based on the average value. Such a process allows a more accurate determination to be made.

Further, the photo interrupters <NUM> through <NUM> do not contact the flat plate part <NUM>. Thus, the photo interrupters <NUM> through <NUM> do not affect the movement of the touchpad <NUM> responding to a touch operation. Non-contact position detection sensors such as electrostatic sensors may be used in place of the photo interrupters <NUM> through <NUM>. Further, contact pressure sensors may be used.

Next, a process for providing tactile feedback in step S10 by the signal processing unit <NUM> will be described. The input device <NUM> according to the present embodiment is configured to produce operation sensations of the two tactile switches that exhibit the vibration characteristics illustrated in <FIG> in accordance with respective input modes. Data of control periods of time, which will be described later, can be stored in the ROM <NUM> in advance. <FIG> is a flowchart illustrating details of a process for providing tactile feedback by the signal processing unit <NUM>.

The input modes may depend on the applications of the input device <NUM>. For example, if the input device <NUM> is provided in the center console of an automobile, the input device <NUM> is used to perform self-driving settings, air conditioner operations, audio equipment operations, and navigation equipment operations. In the present embodiment, two input modes, a self-driving setting mode and an air conditioner operation mode, are assumed to be available. However, any input modes may be set in accordance with the operations in automobiles. Further, input modes may be set in accordance with the types of automobiles. For example, input modes may be different between sedans and sport utility vehicles.

The signal processing unit <NUM> applies a first control signal and a second control signal to the actuator <NUM>. The first control signal is for providing the operation sensation of the tactile switch SW1. The second control signal is for providing the operation sensation of the tactile switch SW2.

In the process for providing the tactile feedback (step S10), the signal processing unit <NUM> first determines whether the current input mode of the input device <NUM> is an input mode for providing the operation sensation of the tactile switch SW1 (first input mode) (step S11). If the signal processing unit <NUM> determines that the current input mode of the input device <NUM> is the input mode for providing the operation sensation of the tactile switch SW1 (first input mode), the process proceeds to step S12. Conversely, If the signal processing unit <NUM> determines that the current input mode of the input device <NUM> is not the first input mode, the current input mode is regarded as an input mode for providing the operation sensation of the tactile switch SW2 and the process proceeds to step S15. For example, the input mode for providing the operation sensation of the tactile switch SW1 may be the air conditioner operation mode, and the input mode for providing the operation sensation of the tactile switch SW2 may be the self-driving setting mode.

In step S12, the signal processing unit <NUM> causes a control voltage applied to the actuator <NUM> to rise (a first timing). As a result, the actuator <NUM> is driven to start the first vibration and cause the movable base <NUM>, the touchpad <NUM>, and the decorative panel <NUM> to be moved in the first direction.

At a second timing at which a predetermined control period of time Δt101 has elapsed (step S13) from the first timing of the rising of the control voltage in step S12, the signal processing unit <NUM> causes the control voltage applied to the actuator <NUM> to fall (step S14). As a result, the state of the actuator <NUM> changes to the initial state. This causes the second vibration to be started and the movable base <NUM>, the touchpad <NUM>, and the decorative panel <NUM> to be moved in a direction opposite to the first direction. At this time, the movable base <NUM>, the touchpad <NUM>, and the decorative panel <NUM> start to be subjected to the combined vibration of the first vibration and the second vibration. The control period of time Δt101 is set to match the duration Δt1 (see <FIG>) of the first period of the combined vibration. For example, the control period of time Δt101 is less than or equal to one half of the period of the first vibration. Further, the second vibration is in a direction that causes the first vibration to converge.

Conversely, in step S15, the signal processing unit <NUM> causes a control voltage applied to the actuator <NUM> to rise (a first timing). As a result, the actuator <NUM> is driven to start the first vibration and cause the movable base <NUM>, the touchpad <NUM>, and the decorative panel <NUM> to be moved in the first direction.

At a second timing at which a predetermined control period of time Δt102 has elapsed (step S16) from the first timing of the rising of the control voltage in step S15, the signal processing unit <NUM> causes the control voltage applied to the actuator <NUM> to fall (step S17). As a result, the state of the actuator <NUM> changes to the initial state. This causes the second vibration to be started and the movable base <NUM>, the touchpad <NUM>, and the decorative panel <NUM> to be moved in the direction opposite to the first direction. At this time, the movable base <NUM>, the touchpad <NUM>, and the decorative panel <NUM> start to be subjected to the combined vibration of the first vibration and the second vibration. The control period of time Δt102 is set to be different from the control period of time Δt101, and is set to match the duration Δt2 (see <FIG>) of the first period of the combined vibration. For example, the control period of time Δt102 is less than or equal to one half of the period of the first vibration. Further, the second vibration is in the direction that causes the first vibration to converge.

The signal processing unit <NUM> performs the above-described process at the time of providing tactile feedback (step S10). Accordingly, the input device <NUM> can provide an operator with tactile feedback that simulates the operation sensation of the tactile switch SW1 or SW2 in accordance with the corresponding input mode.

Note that the number of types of operation sensations provided by the input device according to the present disclosure is not limited to two, and may be three or more. That is, the number of control periods of time, extending from the first timing at which to start the first vibration to the second timing at which to start the second vibration, may be three or more.

The actuator is not limited to the piezoelectric actuator, and may be a magnetic actuator. For example, if a magnetic actuator is used, the signal processing unit <NUM> may start the first vibration by starting to apply the current instead of causing the voltage to rise, and may start the second vibration by stopping to apply the current instead of causing the voltage to fall.

The operation part is not limited to the operation panel member such as the touchpad <NUM>, and may be a push button having an operation surface.

The input device according to the present disclosure is particularly suitable as an input device provided in the center console of an automobile. The driver of the automobile can check his/her touch operation without looking away from the road by receiving tactile feedback from the input device.

Although specific embodiments have been described above, the present invention is not limited to the particulars of the above-described embodiments. Variations and modifications may be made within the scope of the subject matter recited in the claims.

Claim 1:
An input device (<NUM>) comprising:
an operation part (<NUM>), wherein the operation part includes an operation panel member, wherein the operation panel member has a touch surface and is configured to detect coordinates of a touched position within the touch surface;
an actuator (<NUM>) configured to impart a tactile effect to the operation part; and
a controller configured to apply, to the actuator (<NUM>), a control signal for starting to apply a first vibration (v1) to the operation part at a first timing and for starting to apply a second vibration (v2) to the operation part at a second timing after the first timing, such that a combined vibration of the first vibration (v1) and the second vibration (v2) is applied to the operation part, wherein the control signal comprises a voltage rising at the first timing and falling at the second timing,wherein the first vibration (v1) and the second vibration (v2) are at a resonance frequency of the input device (<NUM>) and are independent of each other,
characterized in that the controller is configured to change the combined vibration to two or more different combined vibrations by changing a control period of time that extends from the first timing to the second timing to two or more different control periods of time,
wherein the controller is configured to change the control period of time such that each of the two or more different control periods of time is less than or equal to one half of a period of the first vibration, and
wherein the controller is configured to select the control period of time in accordance with the coordinates of the touched position and an input mode, the input mode being set in accordance with an operation in an automobile.