Tactile presentation device, display device, data terminal device, and tactile presentation method

Abstract

A signal processing device (105) includes: an input unit (106) to which touch positions touched by a user and stimulation types at the touch positions are inputted; a fundamental frequency calculation unit (107) that calculates fundamental frequencies from the detected touch positions; a target waveform calculation unit (108) that modulates the waveforms of the fundamental frequencies by using envelope waveforms of vibrations corresponding to the stimulation types to be presented to the touch positions and that calculates target waveforms of vibrations to be presented to the touch positions; a driving signal calculation unit (109) that multiplies the target waveforms by inverse characteristics of transmission characteristics to the touch positions from a plurality of actuators and that generates driving signals for driving the plurality of actuators; and an output unit (110) that outputs the generated driving signals to the plurality of actuators. The fundamental frequency calculation unit (107) calculates a fundamental frequency on the basis of a first distance that is the minimum distance, among distances between the touch positions and the distances between the touch positions and a support part of a panel, and sets the fundamental frequency higher as the first distance is shorter.

Description

[Technical Field]

[0001] The present disclosure relates to a tactile presentation device, a display device, a data terminal device, and a tactile presentation method. [Background technology]

[0002] The number of public data terminals (e.g., ticket vending machines and ATMs (Automatic Teller Machines)) and personal data terminals (e.g., car navigation systems, smartphones, and tablet PCs (Personal Computers)) equipped with touch panels is increasing. A touch panel is a device that detects input when the panel is touched. Generally, most touch panels are equipped with a liquid crystal display or an organic electroluminescence (EL) display, and are also called touch displays or touch screens. A touch panel detects a user's touch on a GUI (Graphical User Interface) object displayed on the panel or display.

[0003] Such devices generally have the advantage of providing a high degree of freedom in the placement of GUI objects. However, compared to conventional user interfaces that use physical buttons, user interfaces using touch panels make it difficult for users to sense the tactile sensation when pressing a button. This poses a problem, making it difficult for users to recognize whether they have touched the touch panel correctly. To solve this problem, methods have been proposed that vibrate the touch panel to present a tactile sensation (haptic sensation) at the user's touch position (e.g., Patent Documents 1 and 2).

[0004] The devices described in Patent Documents 1 and 2, when multiple positions are touched simultaneously, perform control based on the vibration transmission characteristics from the actuator to the touch positions so that the vibration at a specific touch position is larger than the vibration at other touch positions, and present individual vibrations at each touch position. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] WO2015 / 059887 [Patent Document 2] WO2010 / 038552 Summary of the Invention [Problem to be solved by the invention]

[0006] Conventional tactile presentation devices such as those described in Patent Documents 1 and 2 may require a high driving voltage to present the desired vibration to a touch position when the distance between multiple touch positions is close or when the touch position is close to the support part of the panel.

[0007] Therefore, an object of the present disclosure is to provide a tactile presentation device, a display device, a data terminal device, and a tactile presentation method that are capable of presenting a targeted tactile stimulus with a low driving voltage. [Means for solving the problem]

[0008] A tactile presentation device according to the present disclosure includes a touch panel, a housing supporting the touch panel, a plurality of actuators arranged at different positions so as to vibrate the touch panel, a touch sensor that detects a touch position where a user's finger or a control stick comes into contact with the touch panel, and a signal processing device that receives the detected touch position and the type of stimulus to be presented at the touch position from the touch sensor, generates drive signals to drive each of the plurality of actuators, and outputs the generated drive signals to each of the plurality of actuators. The signal processing device includes an input unit that receives the touch position touched by the user and the type of stimulus at the touch position as input, a fundamental frequency calculation unit that calculates a fundamental frequency from the detected touch position, a target waveform calculation unit that modulates the waveform of the fundamental frequency with an envelope waveform of a vibration corresponding to the type of stimulus to be presented at the touch position and calculates a target waveform of the vibration to be presented at the touch position, a drive signal calculation unit that multiplies the target waveform by the inverse characteristic of the transfer characteristic from each of the plurality of actuators to the touch position to generate a drive signal to drive each of the plurality of actuators, and an output unit that outputs the generated drive signals to the plurality of actuators. The fundamental frequency calculation unit calculates the fundamental frequency based on a first distance, which is the smallest distance between the distance between the touch positions and the distance between the touch positions and the support part of the panel, and the shorter the first distance, the higher the fundamental frequency.

[0009] A tactile presentation method according to the present disclosure is a method for presenting a tactile stimulus to a tactile presentation device including a touch panel, a housing supporting the touch panel, a plurality of actuators arranged at different positions so as to vibrate the touch panel, a touch sensor for detecting a touch position where a user's finger or a control stick comes into contact with the touch panel, and a signal processing device for receiving the detected touch position and the type of stimulus to be presented at the touch position from the touch sensor, generating drive signals for driving each of the plurality of actuators, and outputting the generated drive signals to each of the plurality of actuators. This tactile presentation method includes the steps of: inputting the touch position touched by the user and the type of stimulus at the touch position; calculating a fundamental frequency from the detected touch position; modulating the waveform of the fundamental frequency with an envelope waveform of a vibration corresponding to the type of stimulus to be presented at the touch position to calculate a target waveform of the vibration to be presented at the touch position; multiplying the target waveform by an inverse characteristic of the transfer characteristic from each of the plurality of actuators to the touch position to generate a drive signal for driving each of the plurality of actuators; and outputting the generated drive signals to the plurality of actuators. The step of calculating the fundamental frequency includes a step of calculating the fundamental frequency based on a first distance, which is the smallest distance between the distances between the touch positions and the distance between the touch positions and the support part of the touch panel, and increasing the fundamental frequency as the first distance becomes shorter. [Effects of the Invention]

[0010] According to the tactile presentation device and tactile presentation method of the present disclosure, a targeted tactile stimulus can be presented with a low driving voltage. [Brief explanation of the drawings]

[0011] [Figure 1] 1(a) is a side view of the tactile presentation device 1 of the embodiment 1. FIG. 1(b) is a top view of the tactile presentation device 1 of the embodiment 1. FIG. [Figure 2] 3 is a flowchart showing the operation of the tactile presentation device 1 of the first embodiment. [Figure 3] FIG. 2 is a diagram showing a vibration waveform and an envelope waveform corresponding to a first example of tactile stimulation. [Figure 4] FIG. 10 is a diagram showing a vibration waveform and an envelope waveform corresponding to a second example of tactile stimulation. [Figure 5] FIG. 10 is a diagram showing a vibration waveform and an envelope waveform corresponding to a third example of tactile stimulation. [Figure 6] FIG. 10 is a diagram showing a vibration waveform and an envelope waveform corresponding to a fourth example of tactile stimulation. [Figure 7] 10 is a flowchart showing the detailed procedure of S103. [Figure 8] FIG. 10 is a diagram showing a case where the touch panel 101 is fixed in a continuous area. [Figure 9] 10 is a diagram showing an example of vibration distribution on the touch panel 101. FIG. [Figure 10] 10 is a diagram showing an example of vibration distribution on the touch panel 101. FIG. [Figure 11] 10 is a diagram showing an example of vibration distribution on the touch panel 101. FIG. [Figure 12] 10 is a diagram showing an example of vibration distribution on the touch panel 101. FIG. [Figure 13] 1 is a schematic diagram showing a cross section of a vibration distribution occurring on a certain straight line of the touch panel 101. FIG. [Figure 14] 1 is a schematic diagram showing a cross section of a vibration distribution occurring on a certain straight line of the touch panel 101. FIG. [Figure 15] 1 is a schematic diagram showing a cross section of a vibration distribution occurring on a certain straight line of the touch panel 101. FIG. [Figure 16] 1 is a schematic diagram showing a cross section of a vibration distribution occurring on a certain straight line of the touch panel 101. FIG. [Figure 17] 1 is a schematic diagram showing a cross section of a vibration distribution occurring on a certain straight line of the touch panel 101. FIG. [Figure 18] 10 is a diagram showing points P and Q at a minimum distance Dmin, and a first example of vibrations formed on the touch panel 101. FIG. [Figure 19] 10 is a diagram showing points P and Q at the minimum distance Dmin, and a second example of vibrations formed on the touch panel 101. FIG. [Figure 20]FIG. 11 is a diagram showing the relationship between a provisional fundamental frequency and the fundamental frequency fc in the second embodiment. [Figure 21] FIG. 5 is a block diagram showing the configuration of a display device 500. [Figure 22] FIG. 6 is a block diagram showing the configuration of a data terminal device 600. [Figure 23] FIG. 2 is a diagram illustrating an example of the hardware configuration of a signal processing device 105. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. Detailed descriptions that are more detailed than necessary will be omitted. For example, detailed descriptions of well-known matters and redundant descriptions of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. The inventors provide the accompanying drawings and the following description to enable those skilled in the art to fully understand the present disclosure, and do not intend for them to limit the subject matter described in the claims to be included therein.

[0013] Embodiment 1 <Configuration of the tactile presentation device> FIG. 1(a) is a side view of the tactile presentation device 1 of the first embodiment, and FIG. 1(b) is a top view of the tactile presentation device 1 of the first embodiment.

[0014] 1(a) and 1(b), the tactile presentation device 1 includes a touch panel 101, a housing 102, N (N is an integer equal to or greater than 1) actuators 103_1 to 103_N, a touch sensor 104, and a signal processing device 105. Each of these components will be described below.

[0015] <Touch Panel 101> The touch panel 101 is operated by the user's finger. The touch panel 101 is made of, for example, a plate-like member made of glass or resin. The touch panel 101 may be any member as long as it is strong enough to maintain its shape and capable of transmitting vibrations for presenting tactile stimuli to the user. The size, shape, thickness, and material of the touch panel 101 are not particularly limited.

[0016] The touch panel 101 may be formed integrally with a display (not shown) such as a TFT (Thin Film Transistor) or an organic EL display so as to display image data. When the touch panel 101 and the display are formed integrally, images of buttons or knobs can be displayed on the display. This allows the user to intuitively understand how to perform touch operations. In such a case, the actuators 103_1 to 103_N, which will be described later, are arranged, for example, on the periphery of the touch panel 101 so as not to interfere with the display area.

[0017] <Case 102> The housing 102 supports the touch panel 101. A portion of the housing 102 is connected to the touch panel 101. The support portion 114 is a connection portion between the touch panel 101 and the housing 102. FIG. 1 shows a case in which the touch panel 101 is fixed to the housing 102 via support portions 114_1 to 114_K at K locations (K is an integer of 1 or more). The touch panel 101 is separated from the housing 102 at locations other than the support portions 114_1 to 114_K so as not to come into contact with the housing 102. Note that the connection portion and connection method of the housing 102 are not particularly limited as long as the housing 102 is connected so as to be able to support the touch panel 101. The housing 102 and the touch panel 101 may be connected via a viscoelastic material such as silicone rubber (not shown).

[0018] <Actuator 103> The actuator 103 is attached so as to vibrate the touch panel 101. The actuator 103 is configured, for example, by a voice coil or a piezoelectric vibrator. FIG. 1 shows a configuration in which N (N is an integer equal to or greater than 1) actuators 103_1 to N are attached. The actuators 103_1 to N are arranged at different positions on the touch panel 101. Note that the actuators 103_1 to N may be any actuators that can vibrate the touch panel 101, and there are no particular limitations on their type or how they are attached. One end of the actuators 103_1 to N may be connected to the housing 102. The actuators 103_1 to N may include an amplifier circuit required for driving.

[0019] <Touch sensor 104> The touch sensor 104 detects a position touched by a user's finger. The touch sensor 104 is, for example, a capacitive sheet-like sensor, and is attached to the touch panel 101 to be integrated therewith.

[0020] Touch sensor 104 performs position detection using numerous electrode rows arranged in vertical and horizontal layers, thereby simultaneously detecting multiple touch positions when multiple fingers touch different locations at the same time. The number of touch positions that can be detected simultaneously is designed to match the expected number of simultaneous touches in the intended use of the device. Figure 1 shows a case where M locations are touched simultaneously. Touch sensor 104 may be a sensor other than a capacitive sensor, as long as it can simultaneously detect the expected number of touch positions, and its type and form are not particularly limited.

[0021] <Signal processing device 105> The signal processing device 105 includes an input unit 106, a fundamental frequency calculation unit 107, a target waveform calculation unit 108, a drive signal calculation unit 109, and an output unit 110. Each of these components will be described below.

[0022] <Input section 106> The input unit 106 is an electric circuit equipped with an input interface. In the description of this embodiment, it is assumed that M (M is an integer equal to or greater than 1) touch positions are detected on the touch sensor 104. The input unit 106 receives the M touch positions 111_1 to M detected by the touch sensor 104 and the stimulus types 112_1 to M to be presented to the touch positions 111_1 to M, respectively.

[0023] <Fundamental frequency calculation unit 107> The fundamental frequency calculation unit 107 calculates the fundamental frequency of vibration based on the touch positions 111_1 to 111_M.

[0024] <Target waveform calculation unit 108> The target waveform calculation unit 108 calculates a target waveform of the vibration to be presented to each of the touch positions 111_1 to 111_M, based on the fundamental frequency of the vibration calculated by the fundamental frequency calculation unit 107 and the stimulus types 112_1 to 112_M to be presented to each of the touch positions 111_1 to 111_M.

[0025] <Drive signal calculation unit 109> The drive signal calculation unit 109 calculates drive signals 113_1 to 113_N for the actuators 103_1 to 103_N, respectively, based on the touch positions 111_1 to 111_M and target waveforms of vibrations to be presented to the touch positions 111_1 to 111_M, respectively.

[0026] <Output unit 110> The output unit 110 is an electric circuit having an output interface connected to each of the actuators 103_1 to N. The output unit 110 outputs the drive signals 113_1 to N calculated in the drive signal calculation unit 109 to each of the actuators 103_1 to N.

[0027] The signal processing device 105 (input unit 106, fundamental frequency calculation unit 107, target waveform calculation unit 108, drive signal calculation unit 109, and output unit 110) is configured, for example, by a combination of a general-purpose DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), a memory, an HDD (Hard Disk Drive), an input / output interface circuit, a bus circuit connecting these, an AD converter for inputting and outputting analog signals, a DA converter, an analog filter circuit, an amplifier circuit, or software describing the operation of the DSP. Such signal input / output and arithmetic processing functions can be realized by a combination of various hardware and software, and the specific configuration is not particularly limited as long as the functions are realized.

[0028] <Operation> Next, the operation of the tactile presentation device 1 according to the first embodiment will be described.

[0029] FIG. 2 is a flowchart showing the operation of the tactile presentation device 1 according to the first embodiment. In S101, when a user touches the touch panel 101, the touch sensor 104 attached to the touch panel 101 detects the touch positions 111_1 to 111_M.

[0030] In S102, the input unit 106 of the signal processing device 105 receives input of the touch positions 111_1 to 111_M detected by the touch sensor 104 and the stimulus types 112_1 to 112_M to be presented to the touch positions 111_1 to 111_M, respectively.

[0031] The type of vibration stimulus to be presented at which touch position varies depending on the specifications of the user interface to be provided, and is determined outside the tactile presentation device 1 of this embodiment.

[0032] 3 is a diagram showing a vibration waveform and an envelope waveform corresponding to a first example of tactile stimulation, in which the solid line represents the vibration waveform and the dashed line represents the envelope waveform.

[0033] For example, if the touch position is where a button is displayed, a single, sharp stimulus with a click feeling like pressing a button is appropriate. Therefore, a vibration with a short, sharply changing envelope waveform, as shown by the dashed line in Figure 3, is presented.

[0034] 4 is a diagram showing a vibration waveform and an envelope waveform corresponding to a second example of tactile stimulation, in which the solid line represents the vibration waveform and the dashed line represents the envelope waveform.

[0035] Even if the same single stimulus is presented, when a slightly gentler tactile sensation is presented, a vibration with a gently changing envelope waveform of a slightly longer duration is presented, as shown by the dashed line in Figure 4.

[0036] 5 is a diagram showing a vibration waveform and an envelope waveform corresponding to the third example of tactile stimulation, in which the solid line represents the vibration waveform and the dashed line represents the envelope waveform.

[0037] When the touch position is the display position of the slide bar, a stimulus that repeats continuous clicks in time with the movement of the slide bar is appropriate. Therefore, an envelope waveform vibration with repeating peaks is presented, as shown by the dashed line in Figure 5. When issuing some kind of warning about a touch operation, a stimulus that repeats sharp clicks to attract the user's attention is also appropriate, and an envelope waveform vibration as shown by the dashed line in Figure 5 is presented.

[0038] 6 is a diagram showing a vibration waveform and an envelope waveform corresponding to a fourth example of tactile stimulation, in which the solid line represents the vibration waveform and the dashed line represents the envelope waveform.

[0039] When touching a button for a certain period of time, such as a button that increases or decreases the temperature of an air conditioner, a stimulus that provides a constant tactile sensation is appropriate to let the user know that the touch state is being recognized, and an envelope waveform vibration such as that shown by the dashed line in Figure 6 is presented.

[0040] When the control object touches a position where there is no object, no stimulus is presented. In this case, an envelope vibration whose amplitude is 0 at all times is presented.

[0041] If the arrangement or type of the operation object displayed on the screen changes, the correspondence between the touch position and the stimulus type also changes accordingly.

[0042] The correspondence between the touch positions 111_1 to 111_M and the stimulus types 112_1 to 112_M varies depending on the intention of presenting a tactile stimulus to the user. Therefore, this correspondence is set so that the intended function can be presented to the user when designing application software using the tactile presentation device 1 of this embodiment. In other words, the stimulus types 112_1 to 112_M are determined outside the tactile presentation device 1 and input to the tactile presentation device 1.

[0043] In S103, when the touch positions 111_1 to 111_M and the stimulus types 112_1 to 112_M to be presented to the touch positions 111_1 to 111_M, respectively, are input, the fundamental frequency calculation unit 107, the target waveform calculation unit 108, and the drive signal calculation unit 109 in the signal processing device 105 calculate drive signals for controlling the actuators 103_1 to 103_N by performing calculations according to the procedures of STEPs 1 to 3 described below.

[0044] To prepare for the explanation of STEPs 1 to 3, the handling of data and calculations in fundamental frequency calculation section 107, target waveform calculation section 108, and drive signal calculation section 109 will be explained.

[0045] In the fundamental frequency calculation unit 107, the target waveform calculation unit 108, and the drive signal calculation unit 109, all the time-series data used in the calculation and the data in its frequency domain are to be treated as sampled digital data. As an example, here the sampling frequency is set to 2048 Hz. It is known as the sampling theorem that the sampled data can hold information up to a frequency of half the sampling frequency. If the sampling frequency is 2048 Hz, it is possible to hold a band up to about 1 kHz. The sampling frequency may be determined according to the frequency band of the vibration to be handled. In haptic rendering by vibration, a frequency band centered around 200 - 300 Hz is often used. In that case, a sampling frequency of 2048 Hz is sufficient.

[0046] Each numerical value of the time-series data is also digitized. A data type with sufficient precision is used so that no large calculation error occurs. For example, by using a data type of double-precision floating-point type, the calculation error can be sufficiently suppressed to be small. Here, it is assumed that each numerical value of the time-series data is held as data of double-precision floating-point type.

[0047] In this embodiment, the time-series data is appropriately converted into data in the frequency domain for explanation. Since the data in the time domain and the data in the frequency domain can be mutually converted by the discrete Fourier transform and the inverse discrete Fourier transform, there is no essential difference whether the data storage and calculation are performed in which domain. That is, as long as the data in the time domain and the frequency domain are appropriately associated by the discrete Fourier transform and the inverse discrete Fourier transform, equivalent calculations can be performed in either domain. The configuration of the present invention is not limited to the method of data storage and calculation described in this embodiment.

[0048] FIG. 7 is a flowchart showing the detailed procedure of S103. The calculations performed in STEP1 - 3 of FIG. 7 are described below.

[0049] <STEP1: Calculation of fundamental frequency> The fundamental frequency calculation unit 107 calculates the fundamental frequency f of the vibration waveform to be presented on the touch panel 101 based on the touch positions 111_1 to 111_M. c Calculate.

[0050] fundamental frequency f c The calculation procedure is shown below. The fundamental frequency calculation unit 107 calculates the minimum distance D between any two of the touch positions 111_1 to 111_M and the distance between any two of the touch positions 111_1 to 111_M and any one of the support portions 114_1 to 114_K of the panel. min (Hereafter, the minimum distance D min The minimum distance D min The fundamental frequency calculation unit 107 calculates the distance between each of all combinations of the touch position 111_i and the touch position 111_j (i=1 to M, j=1 to M, i≠j) and the touch position 111_i and the support portion 114_j (i=1 to M, j=1 to K), and determines the minimum distance among the calculated distances as the minimum distance D min Let's say.

[0051] Touch position 111 is the position where the user's hand or finger, or a control stick or the like used to perform operations on touch panel 101, comes into contact with touch panel 101. A control stick is a tool such as a touch pen or touch stick that the user holds in their hand to perform operations on touch panel 101. The shape, material, size, etc. of the control stick are not important as long as it can operate touch panel 101.

[0052] The support portion 114 is a portion of the touch panel 101 that is connected to and fixed to the housing 102. If there are multiple fixed portions, there are multiple support portions 114. Fig. 1 shows a configuration in which there are K support portions 114 (support portions 114_1 to K).

[0053] FIG. 8 is a diagram showing a case where touch panel 101 is fixed in a continuous area. As shown in Fig. 8, when the touch panel 101 is fixed in continuous areas 901A and 901B, several discrete positions P1 to P7 are set to fill the entire area, and support portions 114_a1 to a7 are assumed to be present at these positions P1 to P7. In this case, it is desirable that the intervals between the support portions 114a1 to a3 and a4 to a7 are as narrow as possible, but it is sufficient to set them to the same level as the intervals between candidates for the touch position 111, which will be described later, since this does not cause a large error in calculating the distance between the touch position 111 and the support portions 114. The positions of all the support portions 114 on the touch panel 101 are recorded in advance in a storage device (not shown), such as a nonvolatile memory, and the minimum distance D mentioned above is calculated by referring to this. min is calculated.

[0054] Next, the fundamental frequency calculation unit 107 calculates the minimum distance D min Calculate the frequency that is α times the fundamental frequency f c The smaller the value of the constant α, the more desirable it is, but here we set α = 12. Below, we consider the wavelength as the minimum distance D min A specific method for calculating the frequency that is α times higher than the reference frequency will be described below.

[0055] In general, the wavelength of vibration propagating through a plate-like member such as the touch panel 101 is determined depending on the frequency. For example, it is known that the relationship between the frequency f and wavelength λ of vibration (bending wave) propagating on a flat plate is expressed by equation (1).

[0056]

number

[0057] Here, E is the modulus of elasticity of the material that makes up the plate, ρ is the density, ν is Poisson's ratio, and h is the thickness of the plate.

[0058] The fundamental frequency calculation unit 107 substitutes the physical properties of the touch panel 101 (modulus of longitudinal elasticity E, density ρ, Poisson's ratio ν, thickness h of the flat plate) into equation (1), and further substitutes (D min× α), the wavelength λ is (D min × α), and use this as the fundamental frequency f c Let's say.

[0059] The physical property values ​​of touch panel 101 required for calculating equation (1) may be specification values ​​based on the material and dimensions at the time of design, or may be measured values ​​obtained by separate measurements. In either case, these physical property values ​​are stored in a storage device (not shown), such as a nonvolatile memory, provided in fundamental frequency calculation unit 107, and are used as a reference for calculating equation (1).

[0060] As a method that does not rely on equation (1), it is also possible to create a conversion table in advance that shows the relationship between frequency and wavelength. The relationship between frequency and wavelength can be found by directly measuring the touch panel 101 or by using a technique such as finite element analysis. The conversion table is created using the found results. When this method is used, the created conversion table is stored in a storage device (not shown), such as a nonvolatile memory, provided in the fundamental frequency calculation unit 107, and the fundamental frequency calculation unit 107 calculates the wavelength (D min × α), and this is called the fundamental frequency f c Let's say.

[0061] In this way, the fundamental frequency f c As the minimum distance D min The frequency corresponding to the wavelength α times the wavelength of the

[0062] In this case, the wavelength λ is the minimum distance D min α times the minimum distance D min The length is proportional to the minimum distance D min The shorter the wavelength λ, the shorter the frequency f. On the other hand, as can be seen from equation (1), the frequency f is inversely proportional to the square of the wavelength λ, and the shorter the wavelength λ, the higher the corresponding frequency f. Therefore, the fundamental frequency f calculated here is c is the minimum distance D min The shorter the time, the higher the value.

[0063] Fundamental frequency f c In the calculation of, the minimum distance D among the distances between the touch positions 111_1 to M and the distances between the touch positions 111_1 to M and the support portions 114_1 to K of the panel min The reason for selecting will be described later. Also, the reason for setting the constant α to 12 and the method for setting an appropriate value of α will be described later.

[0064] <STEP2: Calculation of target waveform> The target waveform calculation unit 108 calculates the target waveform Y m (f) of the vibration to be presented at the touch position 111_m (m = 1 to M).

[0065] Y m (f) is data in the frequency domain of a waveform obtained by modulating a sine wave of the fundamental frequency f c with the envelope waveform of the vibration to be presented at the touch position 111_m, and is calculated according to Equation (2).

[0066]

Equation

[0067] In Equation (2) above, DFT represents a Fourier transform and converts a time signal into a frequency signal. sin() is a sine function, f is the frequency, and t is an index representing time.

[0068] <9000526>ENV m (t) (where m is any one of 1 to M) is the envelope waveform of the vibration to be presented at the touch position 111_m and is determined corresponding to the type of stimulus 112_m to be presented.

[0069] For example, when the type of stimulus is a sharp single stimulus such as a click feeling, the envelope waveform is a waveform with a short duration that changes steeply, like the dashed line in Figure 3.

[0070] Even for the same single stimulus, when presenting a slightly gentle tactile sensation, the envelope waveform becomes a waveform with a slightly longer duration that changes smoothly, like the dashed line in FIG. 4. In the case of a stimulus where clicks are continuous, the envelope waveform is a waveform with repeated peaks, like the dashed line in FIG. 5. When a constant stimulus is continuous, the envelope waveform is a waveform that maintains a constant value, like the dashed line in FIG. 6.

[0071] When the touch position 111_m does not present vibration, ENV m (t) = 0, and the target waveform at that position is Y m (f) = 〈u〉0〈 / u〉.

[0072] Here, the solid lines in FIGS. 3 to 6 are the waveforms of Y m (f) for the respective envelope waveforms. Thus, the envelope waveform corresponding to each type of stimulus is determined in advance, and the corresponding table and the data of all the envelope waveforms to be used are stored in a storage device (not shown), such as a non-volatile memory in the target waveform calculation unit 108. The target waveform calculation unit 108 refers to the envelope waveform ENV m (t) corresponding to the input stimulus type 112_m (m = 1 to M) using this corresponding table.

[0073] <STEP3: Calculation of drive signal> The drive signal calculation unit 109 calculates the drive signal 113_n for the actuator 103_n (n = 1 to N).

[0074] The drive signal 113_n is represented as X n (f). The transmission characteristic of the vibration transmitted to the touch position 111_m (m = 1 to M) via the actuator 103_n (n = 1 to N) is G mn (f). f is the frequency index, and X n (f), G mn (f) are data in the frequency domain.

[0075] The vibration transfer characteristics can be calculated by applying a reference signal voltage to each actuator and measuring the vibration generated at the touch position as a response. A wideband signal such as white noise, an impulse, or a time-stretched pulse (TSP) is generally used as the reference signal. For example, candidate touch positions 111_1 to 111_M are set in a grid pattern in an area on the touch panel 101 where touch operations are expected. Then, transfer characteristics data can be measured in advance for all combinations of each of the actuators 103_1 to 103_N and each grid point.

[0076] The measured vibration transfer characteristic data is stored in advance in a storage device (not shown), such as a nonvolatile memory, provided in the drive signal calculation unit 109, and data on the vibration transfer characteristic of the lattice points corresponding to the touch positions 111_1-M is used to calculate the drive signals 113_1-N. If the actual touch positions 111_1-M differ from the positions of the lattice points of the measured transfer characteristic, the vibration transfer characteristic to the lattice point closest to the touch positions 111_1-M may be used as the transfer characteristic to the touch positions 111_1-M, or the transfer characteristic to the touch positions 111_1-M may be obtained by interpolating from the transfer characteristics to several lattice points around the touch positions 111_1-M. The closer the interval between the lattice points, the less likely it is to cause a difference from the actual touch positions 111_1-M, which is desirable, but considering the size of the fingertip, a distance of 1 cm or less is sufficient.

[0077] X n (f) (n=1~N) is the vibration of the touch position 111_m (m=1~M) m (f) So that Y m (f) (m=1 to M) is calculated by multiplying it by a characteristic that cancels the transfer characteristic of vibrations reaching the touch positions 111_1 to 111_M via the actuators 103_1 to 103_N. A specific calculation procedure will be described below.

[0078] The drive signal calculation unit 109 calculates the vibration transmission characteristic G mn (f) is the element of the mth row and nth column of the matrix [G mn (f)] has the inverse property of the matrix [Hnm (f)] is calculated, and Y m (f) is the mth element of the vector [Y m (f)] to [H nm (f)] is multiplied to calculate the vector. The n-th element of the calculated vector is the drive signal X n (f). That is, the drive signal X n (f) is calculated according to equation (3).

[0079]

number

[0080] In addition, [A mn ] is A mn is the element of the mth row and nth column, [B n ] is B n represents a vector whose n-th element is

[0081] where [G mn (f)] is a matrix that has the inverse property of [G mn (f)], and [G mn (f)]×[H nm For example, when the number M of the touch positions 111_1 to 111_M is the same as the number N of the actuators 103_1 to 103_N, that is, when M=N, [H nm (f)] is [G mn On the other hand, if the number M of the touch positions 111_1 to 111_M does not match the number N of the actuators 103_1 to 103_N, the inverse matrix [H nm (f)] can be calculated as a generalized inverse matrix. [H nm (f)] is a generalized inverse matrix, and if N>M, then [G mn (f)]×[H nm It is possible to calculate a matrix such that (f)] is a unit matrix, and when M>N, it is not possible to find an exact inverse matrix, but it is possible to calculate a matrix with approximately inverse characteristics.

[0082] Even if the number M of the touch positions 111_1 to 111_M is the same as the number N of the actuators 103_1 to 103_N, [G mn (f)] may not have an inverse matrix due to rank deficiency. In that case, the inverse matrix [H nm (f)] can be calculated as a generalized inverse matrix, or [cI+G mn (f)]. Here, I is the identity matrix, c is a constant, and the method of finding the inverse matrix by adding cI is known as a method to prevent the inverse matrix from diverging due to rank deficiency. In this case, too, an exact solution cannot be obtained, but a matrix with approximately the inverse characteristics can be calculated.

[0083] As mentioned above, [H nm (f)] can be calculated using many commonly known methods, including approximate solutions, and [G mn However, if the number N of the actuators 103_1 to 103_N is smaller than the number M of the touch positions, [H nm (f)] may significantly degrade the accuracy of the inverse characteristic of the calculated [H nm (f)] is [G mn In order to have a good inverse characteristic of (f)], it is preferable that the number N of the actuators 103_1 to 103_N is equal to or greater than the number M of the touch positions 111_1 to 111_M.

[0084] Through the procedures of STEPs 1 to 3 above, fundamental frequency calculation section 107, target waveform calculation section 108, and drive signal calculation section 109 in signal processing device 105 calculate drive signals 113_1 to 113_N.

[0085] In S104 of FIG. 2, the output unit 110 of the signal processing device 105 outputs the driving signal 113_n(X n (f)) (n=1 to N) is output to the corresponding actuator 103_n.

[0086] The actuator 103_n (n=1 to N) receives a driving signal 113_n (X n(f)) and vibrates, vibrating touch panel 101. At this time, the vibration occurring at touch position 111_m (m=1 to M) is a superposition of the vibrations that occur when actuators 103_1 to 103_N vibrate and reach touch position 111_m.

[0087] That is, the transfer characteristic of the vibration transferred to the touch position 111_m (m=1 to M) via the actuator 103_n (n=1 to N) is G mn Since it is (f), the vibration waveform Y′ generated at the touch position 111_m m (f) is expressed by equation (4).

[0088]

number

[0089] Here, referring to equation (3), the following equation holds:

[0090]

number

[0091] [H nm (f)] is [G mn (f)], the matrix with the inverse characteristics of the vibration transfer characteristics [G mn (f)] and the matrix [H nm (f)] cancel each other out, and the vibration waveform Y′ presented to each touch position 111_m m (f) is the target waveform Y m The waveform is roughly the same as (f).

[0092] <Action and effect> In the fundamental frequency calculation unit 107 of the tactile presentation device of this embodiment, the fundamental frequency f c The function and effect of calculating the above will be explained.

[0093] <Fundamental frequency f c and vibration distribution> In this embodiment, the target waveform Y m (f) is the fundamental frequency f c The waveform is a modulated sine wave of the drive signal X n (f) is also the target waveform Y m (f) multiplied by the vibration transmission characteristic. Therefore, the actuator 103 generates a signal with a fundamental frequency f c As can be seen from equation (1), once the frequency f is determined, the corresponding wavelength λ is also determined. The vibration propagating from each actuator 103 onto the touch panel 101 has its fundamental frequency f c The wavelength corresponding to (hereafter, this wavelength is referred to as λ c This results in a sinusoidal vibration of the

[0094] The vibrations generated on the touch panel 101 are the superposition of propagating waves from each of the actuators 103 and reflected waves from the edges. By changing the magnitude and phase of the drive signals 113 that drive each of the actuators 103, various vibration distributions can be formed, including traveling waves and standing waves.

[0095] However, in either case, the wavelength λ propagates from each of the actuators 103. c The vibration on the touch panel 101 formed by the superposition of these vibrations has a wavelength of approximately λ c The vibration distribution changes sinusoidally.

[0096] 9 to 12 are diagrams showing examples of vibration distribution on touch panel 101. FIG. Figure 9 shows the c Figure 10 shows an example of the vibration distribution at a certain moment when f is 200Hz. c Figure 11 shows another example of the distribution when f is 200 Hz. c Figure 12 shows an example of the distribution when f is 300Hz. c This shows another example of the distribution when the frequency is 300 Hz.

[0097] The vibration displacement is illustrated by shades of color (black and white), with darker (closer to black) areas indicating larger vibration displacement (larger in the positive direction) and lighter (closer to white) areas indicating smaller vibration displacement (larger in the negative direction). The dashed circle indicates the position of the actuator 103. An example of vibration distribution for a configuration with six actuators 103 is shown. The vibration distribution only shows the area inside where the actuators 103 are located, where touch operations are performed.

[0098] Figures 9 and 10 show the fundamental frequency f c 11 and 12 show the vibration distribution when the fundamental frequency f is 200 Hz, but the vibration distribution differs because the magnitude and phase of the signals driving each of the actuators 103 are different. c 11 and 12 show the vibration distribution when the frequency is 300 Hz, but the difference in the vibration distributions in Fig. 11 and 12 is due to the difference in the magnitude and phase of the signals that drive each of the actuators 103. In this way, various vibration distributions can be formed by changing the magnitude and phase of the signals that drive each of the actuators 103.

[0099] However, in all of FIGS. 9 to 12, the vibration distribution on touch panel 101 does not become discontinuous at adjacent positions, but is distributed while varying in a roughly sinusoidal wave shape.

[0100] 9 and 10, the vibration distributions are different, but the positive and negative vibration regions are distributed at roughly the same intervals. This is because the signals that drive each of the actuators 103 have the same frequency even though they have different magnitudes and phases, and the wavelengths of the vibrations generated on the touch panel 101 are the same. Similarly, when comparing FIGS. 11 and 12, the positive and negative vibration regions are distributed at roughly the same intervals. This is also because the signals that drive each of the actuators 103 have the same frequency, and the wavelengths of the vibrations generated on the touch panel 101 are the same.

[0101] On the other hand, when comparing the intervals between the regions where the positive and negative signs of the vibration are inverted between Figures 9 and 10 and Figures 11 and 12, the intervals are narrower in Figures 11 and 12 than in Figures 9 and 10. In other words, the vibration distribution in Figures 9 and 10 changes gradually in space, whereas the vibration distribution in Figures 11 and 12 changes suddenly in space. This is because the fundamental frequency f in Figures 9 and 11 is smaller than that in Figures 1 and 12. c is low, and the wavelength of the vibration that occurs is λ c This is because the length becomes longer.

[0102] <Fundamental frequency f c and driving voltage> Since the vibrations on the touch panel 101 are distributed in a continuous sinusoidal wave pattern, vibrations occurring at close positions on the touch panel 101 are similar to each other. c The lower the wavelength λ c Since the distance between the touch panel 101 and the touch panel 102 is longer, the change in the vibration distribution on the touch panel 101 becomes gentler, and the difference in vibration occurring at two adjacent points separated by a certain distance becomes smaller.

[0103] When presenting separate target vibrations to two touch positions 111 located close to each other, or when presenting a target vibration to a touch position 111 close to the support part 114, the drive signal 113 obtained in STEP 3 is calculated to amplify the minute vibration difference between the two points to form different vibrations. As a result, the wavelength λ c The longer is, that is, the longer the fundamental frequency f c The lower the value, the larger the drive signal 113 becomes, and therefore the larger the drive voltage required to output the drive signal 113 becomes.

[0104] This point will be explained in detail below. 13 to 17 are schematic diagrams showing cross sections of vibration distribution occurring on a certain straight line on touch panel 101. The vibration distributions shown in Fig. 13 to 17 are standing waves, and as shown in each figure, nodes (positions where the amplitude of vibration is 0) and antinodes (positions where the amplitude of vibration is maximum) are formed.

[0105] 13 shows the vibration waveform of Case 1. In Case 1, a target vibration is presented at one touch position 111.

[0106] If the vibration presentation position is set to point Q and a standing wave is formed so that the position of point Q is the antinode, the standing wave can vibrate at its maximum amplitude, which is the most efficient way to present a large vibration. In other words, by adjusting the amplitude and phase of the drive signal 113 of each actuator 103 and forming a vibration distribution so that point Q is the antinode of the vibration, the target vibration can be presented with a small drive signal 113, i.e., a low drive voltage.

[0107] Figure 14 shows the vibration waveform of Case 2. In Case 2, the fundamental frequency f c is 200 Hz, and one of two touch positions 111 located close to the other is kept without vibration (the magnitude of vibration is 0), while the target vibration is presented to the other touch position.

[0108] The position to be kept vibration-free is defined as point P, and the target vibration is presented at point Q, a certain distance d away from point P. In order to make point P vibration-free, it is necessary to form a standing wave that becomes a node at point P. In this case, if the distance d is short, the vibration distribution is continuous, so point Q cannot become an antinode of the standing wave, and the magnitude of the vibration generated at point Q becomes smaller than the maximum amplitude of the standing wave. To explain in more detail, the magnitude of the vibration generated at point Q is determined by the distance d between P and Q being the wavelength λ c The phase difference is determined by the phase difference (2πd / λ c ) so the maximum amplitude of the standing wave is |sin(2πd / λ c )| times. To present the same magnitude of vibration at point Q as in Case 1, the magnitude of vibration at point Q must be |1 / sin(2πd / λ c )| times, the drive signal 113 must also be increased by that amount. Note that |*| is an arithmetic symbol that represents the absolute value of *. Furthermore, in this specification, all phases are expressed in radians.

[0109] From the above, in Case 2, where one of two touch positions 111 separated by a distance d is kept vibration-free while the other is presented with a target vibration, the vibration intensity is approximately |1 / sin(2πd / λ) compared to Case 1, where the target vibration is presented to one touch position 111. c )| A drive signal 113 and its drive voltage that are twice as large are required.

[0110] Next, referring to Figures 14 and 15, the fundamental frequency f c The drive signal 113 when the drive voltage is different and the drive signal 113 when the drive voltage is different will be described.

[0111] Figure 15 shows the vibration waveform of Case 3. In Case 3, the fundamental frequency f c At 300H, one of two touch positions 111 located close to each other is kept without vibration (the magnitude of vibration is 0), while the other touch position is presented with a target vibration.

[0112] In both Case 2 and Case 3, the vibration changes sinusoidally with respect to the position, but the fundamental frequency f c Case 2 (Fig. 14) has a lower wavelength λ c The fundamental frequency f c Case 3 (Fig. 15) has a higher wavelength λ c As in Case 2, Case 3 also forms a node of the standing wave at point P to maintain no vibration, and presents the target vibration at point Q, a certain distance d away from point P. In this case, the vibration generated at point Q has a wavelength λ c Phase difference at distance d (2πd / λ c ) and the maximum amplitude of the standing wave is determined by |sin(2πd / λ c )| times larger. In other words, in the range where the distance d is small, the wavelength λ c The longer the c), the oscillation at point Q becomes smaller. To compensate for this and present the same magnitude of oscillation at point Q as in Case 1, c )|| times larger is required, so in the range where the distance d is small, the wavelength λ c The longer the c ) the drive signal 113 and the drive voltage required for its output must be increased.

[0113] For example, comparing Figure 14 and Figure 15, the fundamental frequency f c Case 2 (Fig. 14) with a lower fundamental frequency f c In Case 2, where the value is lower, the driving signal 113 must be made larger.

[0114] In Case 2 and Case 3, the case where the amplitude of vibration at point P is 0 has been described, but a case where the amplitude of vibration is not 0 will be described.

[0115] Figure 16 shows the vibration waveform of Case 4. In Case 4, individual vibrations with non-zero amplitudes are presented at both points P and Q.

[0116] The solid line in Figure 16 represents a standing wave formed so that point P becomes a node. By amplifying the vibration generated at point Q at this time to a target magnitude, it is possible to present the target vibration at point Q while keeping point P vibration-free. The drive signal at this time is referred to as the first drive signal. Similarly, the dashed dotted line in Figure 16 represents a standing wave formed so that point Q becomes a node. By amplifying the vibration generated at point P at this time to a target magnitude, it is possible to present the target vibration at point P while keeping point Q vibration-free. The drive signal at this time is referred to as the second drive signal.

[0117] If the actuator 103 is driven by a signal obtained by adding the first drive signal and the second drive signal, it is possible to present individual target vibrations at points P and Q. Therefore, the drive signal 113 is a signal obtained by adding the first drive signal and the second drive signal, but both the first drive signal and the second drive signal are |1 / sin(2πd / λ) in Case 1. c )| times larger than Case 1, the drive signal 113 obtained by combining the two also becomes roughly |1 / sin(2πd / λ c )|It can be seen that it becomes twice as large.

[0118] From the above, in order to present individual vibrations to two touch positions 111 that are close to each other, |1 / sin(2πd / λ) c )|, and the drive signal 113 and its drive voltage are required, and the wavelength λ c is long, and the fundamental frequency f c The lower the voltage, the greater the magnitude of the drive signal 113 and its drive voltage.

[0119] 17 shows the vibration waveform of Case 5. In Case 5, vibration is presented at touch position 111 close to support portion 114.

[0120] Since the support portion 114 is a portion that restrains the touch panel 101, the vibration distribution on the touch panel 101 is a sinusoidal distribution in which the vibration magnitude becomes 0 at the position of the support portion 114. In other words, point P, which maintained no vibration in Case 2, can be replaced with the support portion 114. The vibration occurring at point Q, which is a certain distance d away from the support portion 114, is |sin(2πd / λ c )|It becomes twice as large.

[0121] Therefore, when vibration is presented to the touch position 111 close to the support part 114, the magnitude of the drive signal 113 is |1 / sin(2πd / λ) c )|. The wavelength λ c is long, and the fundamental frequency f cThe lower the value, the larger the drive signal 113 and its drive voltage will be required.

[0122] <Comparison with reference example> In light of the above, the operation and effect of the tactile presentation device of this embodiment will be explained by comparison with a reference example.

[0123] The difference between the reference example and the first embodiment is that the fundamental frequency f c This is the configuration of the fundamental frequency calculation unit 107 that calculates the fundamental frequency.

[0124] In the reference example, the fundamental frequency f calculated by the fundamental frequency calculation unit 107 is c is not calculated in the procedure of STEP 1 in the first embodiment, but is determined in advance as a constant.

[0125] The difference between the tactile presentation device of the reference example and the tactile presentation device of the first embodiment is that the fundamental frequency f c In other words, in the reference example, the calculation procedure is only a predetermined f c Using the value of the target waveform Y m (f), and the driving signal X n (f) is calculated. The fundamental frequency f c The details other than the calculation procedure are the same as those of the tactile presentation device of the first embodiment, and therefore will not be described repeatedly.

[0126] As described above, the minimum distance D between any two points of the touch positions 111 and any one of the touch positions 111 and the support portion 114 is min On the other hand, the drive signal 113 is |1 / sin(2πD min / λ c )| is proportional to

[0127] In the tactile presentation device of the reference example, the fundamental frequency f c Since is predetermined, the corresponding wavelength λ c is also fixed. Therefore, D minThe smaller the distance D, the larger the drive signal 113. In other words, when two adjacent points are touched or when a position close to the support portion 114 is touched, the minimum distance D min As a result, the magnitude of the drive signal 113 for presenting the target vibration at each touch position 111 increases.

[0128] When the drive signal 113 becomes large in this way, a large drive voltage is required to output it, and the power consumption of the device increases. In addition, since there is generally a limit to the maximum voltage that a device can output, if the voltage of the drive signal 113 exceeds the limit value, the desired vibration cannot be presented.

[0129] In contrast, in the tactile presentation device of this embodiment, the minimum distance D min The smaller is, the greater the fundamental frequency f c (i.e., wavelength λ c (so that is short), the fundamental frequency f c The minimum distance D is determined. min When is small, the wavelength λ c The wavelength λ c The minimum distance D to min Phase (2πD min / λ c ) is kept larger than the reference example. In other words, the minimum distance D min Even if the voltage is small, the magnitude of the drive signal 113 can be suppressed, making it possible to operate at a low voltage.

[0130] In particular, as in this embodiment, the fundamental frequency f c and the corresponding wavelength λ c (D min In the configuration where the minimum distance D is determined to be equal to min The phase difference between two points separated by a distance is always a constant value, as shown below.

[0131]

number

[0132] The drive signal has a value proportional to the following formula:

[0133]

number

[0134] That is, the magnitude of the drive signal 113 is the minimum distance D min is always kept at a constant magnitude corresponding to a phase difference of (2π / α).

[0135] Therefore, even when two adjacent points are touched or when a position close to the support portion 114 is touched, the voltage required to output the drive signal 113 remains roughly the same. Therefore, while presenting a target vibration at each touch position 111, operation at a low voltage is possible without increasing the voltage required to output the drive signal 113.

[0136] <How to set the constant α> Next, an effective setting of the constant α will be described.

[0137] First, considering that the vibration distributed on the touch panel 101 is sinusoidal, the minimum distance D min is the wavelength λ c If the distance is 1 / 4, that is, (π / 2) in phase, the difference in vibration will be the largest, and the minimum distance D min This makes it easier to present different vibrations at positions that are only a few meters apart.

[0138] From equation (6), the minimum distance D min The phase difference corresponding to this is (2π / α), so when α = 4, the phase difference becomes (π / 2). Therefore, when α = 4, equation (7) representing the magnitude of drive signal 113 also becomes the minimum value of 1, and it can be seen that the magnitude of drive signal 113 is most suppressed.

[0139] Next, the minimum distance D min The case where the phase difference (2π / α) for is smaller than (π / 2), that is, the case where α is in a range greater than 4, will be described.

[0140] Since the magnitude of the drive signal 113 is proportional to the value of equation (7), the larger α is, the larger the magnitude of the drive signal 113 is. However, the minimum distance D min Since the phase difference ensured between two points spaced apart by this distance is determined and the required drive voltage can be estimated, the constant α can be set according to the drive voltage allowed by the device.

[0141] For example, when α = 6, the phase difference in equation (6) is (π / 3), and the value of equation (7) representing the magnitude of the drive signal 113 is approximately 1.15. When α = 4, the value of equation (7) is 1, so a drive voltage approximately 1.15 times higher is required compared to when α = 4. When α = 12, the phase difference in equation (6) is (π / 6), and the value of equation (7) representing the magnitude of the drive signal 113 is 2. In other words, a drive voltage approximately twice as high is required compared to when α = 4. When α = 100, the phase difference in equation (6) is (π / 50), and the value of equation (7) representing the magnitude of the drive signal 113 is approximately 15.9. In other words, a drive voltage approximately 15.9 times higher is required compared to when α = 4.

[0142] However, it is not desirable to make the voltage range that the device can tolerate too large in terms of device design and cost. If the driving voltage margin that can be secured is about twice as large as practical, then α should be set to 12 or less, and the wavelength λ c is the minimum distance D min The fundamental frequency f must be less than 12 times c It is appropriate to determine α=12 in this embodiment.

[0143] Next, the minimum distance D min The case where the phase difference (2π / α) for is greater than (π / 2), that is, the case where α is in a range smaller than 4, will be described.

[0144] When α is smaller than 4, the phase difference in equation (6) becomes larger than (π / 2), and the value of equation (7) representing the magnitude of the drive signal 113 becomes larger than when α=4 (phase difference (π / 2)). However, if the propagation direction of the vibration formed on the touch panel 101 is smaller than the minimum distance D min If the direction does not match the direction connecting the two points in min The wavelength generated in the direction connecting the two points at is wavelength λ c This will be described in detail with reference to FIGS.

[0145] Figure 18 shows the minimum distance D min 1 is a diagram showing points P and Q located on a plane, and a first example of vibrations formed on the touch panel 101. FIG.

[0146] In Figure 18, the minimum distance D min The direction connecting points P and Q on the touch panel 101 coincides with the propagation direction of the vibration generated on the touch panel 101. min is the wavelength λ c Since this is greater than 1 / 4 (i.e., the phase difference is (π / 2)), if point P is at the node position of the standing wave, point Q will exceed the position of the antinode, and no large vibration will be obtained.

[0147] Figure 19 shows the minimum distance D min 10 is a diagram showing points P and Q located on the screen and a second example of vibrations formed on the touch panel 101. FIG.

[0148] In Figure 19, the minimum distance D min The direction connecting points P and Q on the touch panel 101 does not match the propagation direction of the vibration generated on the touch panel 101. c Even if the wavelength in the direction connecting points P and Q (λ in Figure 19) c ′) is λ c In Figure 19, the minimum distance D min is the wavelength λ cSince the phase difference is exactly 1 / 4 of ' (i.e., (π / 2)), when point P is at the node of the standing wave, point Q is at the antinode, and large vibrations can be generated.

[0149] That is, if α is greater than 4 and the minimum distance D min If the phase difference (2π / α) with respect to the minimum distance D becomes larger than (π / 2), the magnitude and phase of the signal driving each of the actuators 103 are adjusted. min The wavelength in the direction connecting two points is the minimum distance D min Therefore, the magnitude of the drive signal 113 and the drive voltage required to output it are approximately the same as when α=4 (phase difference (π / 2)).

[0150] From the above, we set α to 4 or less and wavelength λ c is the minimum distance D min The fundamental frequency f must be less than four times c By determining the value of the driving voltage, the magnitude of the driving signal 113 can be minimized, and the driving voltage reduction effect of this embodiment can be sufficiently obtained.

[0151] <Minimum distance D min Based on the fundamental frequency f c Reasons for calculating In this embodiment, the minimum distance D between the distances between the touch positions 111_1 to 111_M and the distances between the touch positions 111_1 to 111_M and the support portions 114_1 to 114_K of the panel is min Select the minimum distance D min Based on the fundamental frequency f c The reason for this will be explained below.

[0152] As described above, when presenting separate vibrations to two touch positions 111 on the touch panel 101, or when presenting vibration to the touch position 111 close to the support portion 114, the fundamental frequency f c If the distance between the two points is the same, the closer the distance between the two points, the larger the drive signal 113 will be.

[0153] Therefore, the magnitude of the drive signal 113 is set to a fundamental frequency f so that the drive voltage can be sufficiently suppressed at the two closest points among the two touch positions 111 and the combination of the support portion 114 and the touch position 111. c Once the driving voltage is determined, a voltage exceeding this driving voltage is not required when presenting vibration to other touch positions 111.

[0154] That is, the magnitude of the drive signal 113 is determined by the distance D between the two closest points among the two touch positions 111 and the combination of the support portion 114 and the touch position 111. min Therefore, the minimum distance D min Based on the fundamental frequency f c By determining the above, it becomes possible to present the target vibration to all touch positions 111.

[0155] As described above, the tactile presentation device of this embodiment can operate at a low voltage without increasing the voltage required to output the drive signal 113, while presenting a desired vibration at the touch position 111.

[0156] Embodiment 2 The tactile presentation device of the second embodiment is the same as the tactile presentation device 1 of the first embodiment, except that the fundamental frequency f c Calculation procedure of the fundamental frequency f c Therefore, the description of the operations from STEP 2 onwards will not be repeated. The tactile presentation device of this embodiment will be described below, focusing on the differences from the first embodiment.

[0157] <Differences in configuration and operation> The difference between this embodiment and the first embodiment is that the fundamental frequency f c When calculating the wavelength, the minimum distance D min When the frequency that is α times the fundamental frequency f (this frequency is referred to as the provisional fundamental frequency in this embodiment) is 300 Hz or more, c is set to 300Hz.

[0158] FIG. 20 shows the tentative fundamental frequency and the fundamental frequency f c 20, for example, by following the procedure of STEP 1, the minimum distance D min Assume that the tentative fundamental frequency calculated based on the constant α and equation (1) is 700 Hz. In this case, in this embodiment, the fundamental frequency calculation unit 107 calculates the fundamental frequency f c Set to 300Hz.

[0159] <Action and effect> The action and effect will be explained below.

[0160] In the first embodiment, the minimum distance D min α times the wavelength λ c so that the fundamental frequency f c Therefore, the minimum distance D min The shorter the wavelength λ c is shorter, so the calculated fundamental frequency f c The value of becomes larger.

[0161] However, it is known that the tactile sense of human fingers is highly sensitive to vibrations with frequencies around 100 to 300 Hz due to the properties of Pacinian corpuscles, a type of mechanoreceptor. However, at frequencies above 300 Hz, the sensitivity of the fingers to vibrations gradually decreases, making it difficult to sense the sensation of touch.

[0162] Human hearing is most sensitive to sounds in the 1 to 4 kHz range, and in the range below 1 kHz, the higher the frequency, the higher the sensitivity. Therefore, in the 100 to 300 Hz range, the fundamental frequency f c As the frequency of the vibration increases, the user will be more likely to perceive the vibration as sound. However, such unintentional sounds should not be perceived by the user. From the viewpoint of sound perception, the fundamental frequency f c It is desirable to set it as low as possible.

[0163] That is, in the first embodiment, the minimum distance Dmin When is small, the fundamental frequency f c If the fundamental frequency f becomes too large, the tactile sensitivity of the human finger may decrease, making it difficult to feel the vibration stimulus. c If the value of becomes too large, it becomes noticeable as a sound, and the user may hear an unnecessary sound.

[0164] Considering this point, in the second embodiment, the fundamental frequency f c The upper limit of the minimum distance D is set to 300 Hz, which is the frequency at which the tactile sensitivity of a human finger is excellent. This reduces the voltage required to output the drive signal 113 while presenting the desired vibration at the touch position 111 to the extent possible, enabling operation at a low voltage. min If the frequency corresponding to the wavelength α times greater than 300 Hz, the fundamental frequency f c This allows us to present tactile sensations with vibrations at a frequency that is easy to perceive, without producing unpleasant sounds.

[0165] Embodiment 3 <Display device> As an apparatus using the tactile presentation device of this embodiment, it is also possible to configure a display device equipped with the tactile presentation device of this embodiment.

[0166] FIG. 21 is a block diagram showing the configuration of a display device 500. As shown in FIG. The display device 500 includes a tactile presentation device 1 and a display 800. The touch panel 101 included in the tactile presentation device 1 is formed integrally with the display 800, such as a TFT or organic EL display, so that image data can be displayed. This not only enables operation at a low voltage while presenting a desired tactile stimulus at the touch position 111, but also allows GUI objects such as buttons, knobs, or slide bars to be displayed as images on the touch panel 101, allowing the user to intuitively understand how to perform touch operations.

[0167] Embodiment 4 <Data Terminal Equipment> As another device using the tactile presentation device of this embodiment, it is also possible to configure a data terminal device equipped with the tactile presentation device of this embodiment. Here, the data terminal device is a device that has a function for a user to input data by touch operation, and examples thereof include automatic ticket vending machines, ATMs, car navigation systems, smartphones, and tablet PCs.

[0168] FIG. 22 is a block diagram showing the configuration of data terminal equipment 600. The data terminal device 600 comprises a tactile presentation device 1, a display 800, and a setting unit 900. The touch panel 101 included in the tactile presentation device 1 is formed integrally with the display 800, such as a TFT or organic EL display, so as to be able to display image data. The setting unit 900 comprises a setting unit (not shown) that outputs a stimulus type 112 according to the displayed content to the input unit 106. This not only enables low-voltage operation while presenting a desired tactile stimulus at the touch position 111, but also makes it possible to present an appropriate tactile sensation according to the type and arrangement of displayed GUI objects such as buttons, knobs, and slide bars.

[0169] <Example of hardware configuration of signal processing device> FIG. 23 is a diagram illustrating an example of the hardware configuration of the signal processing device 105. As shown in FIG.

[0170] When the functions of the signal processing device 105 are realized using software, the signal processing device 105 can, for example, be equipped with a processor 5002 and a memory 5001 connected by a bus 5003, as shown in FIG. 2, and the processor 5002 can execute a program stored in the memory 5001.

[0171] As described above, Embodiments 1 and 2 have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to these, and embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate are possible. Furthermore, it is also possible to combine the components described in Embodiments 1 and 2 above to create new embodiments. [Explanation of symbols]

[0172] 1 tactile presentation device, 101 touch panel, 102 housing, 103 actuator, 104 touch sensor, 105 signal processing device, 106 input unit, 107 fundamental frequency calculation unit, 108 target waveform calculation unit, 109 drive signal calculation unit, 110 output unit, 111 touch position, 112 stimulus type, 113 drive signal, 114 support unit, 500 display device, 600 data terminal device, 800 display, 900 setting unit, 5001 memory, 5002 processor, 5003 bus.

Claims

1. Touch panel and a housing that supports the touch panel; a plurality of actuators arranged at different positions so as to vibrate the touch panel; a touch sensor that detects a touch position where a user's finger or a control stick comes into contact with the touch panel; a signal processing device that receives the touch position detected by the touch sensor and a type of stimulus to be presented at the touch position, generates a drive signal to drive each of the plurality of actuators, and outputs the generated drive signal to each of the plurality of actuators; The signal processing device includes: an input unit into which the touch position touched by the user and the type of stimulation at the touch position are input; a fundamental frequency calculation unit that calculates a fundamental frequency from the detected touch position; a target waveform calculation unit that modulates the waveform of the fundamental frequency with an envelope waveform of a vibration corresponding to the type of stimulus to be presented at the touch position, and calculates a target waveform of the vibration to be presented at the touch position; a drive signal calculation unit that multiplies the target waveform by an inverse characteristic of a transfer characteristic from each of the plurality of actuators to the touch position to generate the drive signal that drives each of the plurality of actuators; an output unit that outputs the generated drive signals to a plurality of actuators, The fundamental frequency calculation unit calculates the fundamental frequency based on a first distance, which is the shortest distance between the distance between the touch positions and the distance between the touch positions and a support portion of the touch panel, and the shorter the first distance, the higher the fundamental frequency.

2. The tactile presentation device according to claim 1 , wherein the fundamental frequency calculation unit sets an upper limit of the fundamental frequency to 300 Hz.

3. 3. The tactile presentation device according to claim 1, wherein the fundamental frequency calculation unit calculates the fundamental frequency so that a wavelength of the fundamental frequency is proportional to the first distance.

4. 4. The tactile presentation device according to claim 1, wherein the fundamental frequency calculation unit calculates the fundamental frequency so that a wavelength of the fundamental frequency is smaller than four times the first distance.

5. A tactile presentation device according to any one of claims 1 to 4; a display unit formed integrally with the touch panel and configured to display GUI objects for operation.

6. A tactile presentation device according to any one of claims 1 to 4; a display unit formed integrally with the touch panel and displaying GUI objects for operation; a setting unit that outputs the stimulus type corresponding to the content to be displayed on the display to the input unit.

7. Touch panel and a housing that supports the touch panel; a plurality of actuators arranged at different positions to vibrate the touch panel; a touch sensor that detects a touch position where a user's finger or a control stick comes into contact with the touch panel; a signal processing device that receives the touch position detected by the touch sensor and a type of stimulus to be presented at the touch position, generates a drive signal for driving each of the plurality of actuators, and outputs the generated drive signal to each of the plurality of actuators, a step of inputting the touch position touched by the user and the type of stimulation at the touch position; calculating a fundamental frequency from the detected touch position; modulating the waveform of the fundamental frequency by an envelope waveform of vibration corresponding to the type of stimulus to be presented at the touch position, and calculating a target waveform of the vibration to be presented at the touch position; generating the drive signal for driving each of the plurality of actuators by multiplying the target waveform by an inverse characteristic of a transfer characteristic from each of the plurality of actuators to the touch position; and outputting the generated drive signals to a plurality of actuators; The step of calculating the fundamental frequency includes a step of calculating the fundamental frequency based on a first distance that is the shortest distance between the distances between the touch positions and the distance between the touch positions and a support portion of the touch panel, and increasing the fundamental frequency as the first distance becomes shorter.

8. The tactile presentation method according to claim 7 , wherein the step of calculating the fundamental frequency includes a step of setting an upper limit of the fundamental frequency to 300 Hz.

9. The tactile presentation method according to any one of claims 7 to 8, wherein the step of calculating the fundamental frequency includes a step of calculating the fundamental frequency so that a wavelength of the fundamental frequency is proportional to the first distance.

10. The tactile presentation method according to any one of claims 7 to 9, wherein the step of calculating the fundamental frequency includes a step of calculating the fundamental frequency so that a wavelength of the fundamental frequency is smaller than four times the first distance.

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