JP2009063741A - Keyboard device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust key-touch feeling to optional touch feeling with simple and light structure. <P>SOLUTION: A keyboard device 1 provided with swingably supported keys 10 and a reactive force generating means, which generates reactive force to key 10 pressing operations, is provided with an electrically active polymer 20 composed of an elastic material which is deformed by the application of a voltage as the reactive force generating means. By this, the reactive force-generating means is remarkably simplified, compared with an ordinary mechanical structure, to lighten the keyboard 1. In addition, a voltage applied to the electrically active polymer 20 is controlled to optionally set the reactive force (performance resistance feeling) to the key-pressing operations, and key 10 touch feeling can freely be adjusted. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a keyboard device suitable for use in an electronic keyboard instrument such as an electronic piano or an electronic organ.

  In a conventional acoustic piano, a touch feeling of a key during performance, that is, a feeling of performance resistance of a key is generated by an action structure including a hammer and a damper. In addition, in electronic keyboard instruments such as electronic pianos and electronic organs, conventional acoustic pianos, etc. can be provided by attaching weights to the keys or by providing mass bodies that provide reaction force against key presses in conjunction with key movements. It is performed to give a feeling of performance resistance similar to that of a keyboard instrument.

  In these keyboard instruments, the performance resistance of the key is uniquely determined by the structure of the action, the weight attached to the key, or the weight of the mass body. Therefore, the touch feeling of the key set in the keyboard instrument cannot be changed to an arbitrary touch feeling. However, performers of keyboard instruments have a wide range of ages, from infants to the elderly, and varying degrees of proficiency with keyboard instruments from beginners to skilled performers. Therefore, it is desired that each player can freely change the touch feeling of the key according to the personal suitability and preference. It is also preferable that the touch feeling of the key can be changed depending on the type and tone color of the musical sound generated by the electronic musical instrument (for example, piano tone color, organ tone color, etc.). Considering this point, Patent Document 1 or Patent Document 2 discloses a keyboard device that can change the touch feeling of a key.

  The keyboard device of Patent Document 1 has a structure for adjusting a touch feeling of a key by a mechanical mechanism. This keyboard device includes a key and a weight that produces a feeling of performance resistance against the key depression, and the engagement position between the key and the weight can be set to an arbitrary position within the stroke of the key depression. Specifically, the position of the rail contacting the free end of the weight is adjusted by a position setting means such as a lever or a solenoid, so that the engagement position of the weight with respect to the key can be adjusted. Thereby, the range in which the key receives a reaction force from the weight when the key is pressed can be set to an arbitrary range within the stroke of the key press.

The keyboard device of Patent Document 2 includes a mechanism for electrically controlling the touch feeling of a key. In this keyboard device, a magnet and a coil are used as means for generating a feeling of performance resistance against key depression. Specifically, feedback correction is performed by detecting the operation of the key with a sensor provided for each key, and based on this, performance resistance generated by the magnet and the coil is adjusted.
Japanese Patent No. 3480749 Japanese Patent No. 2748616

  Since the keyboard device described in Patent Document 1 is configured to adjust the touch feeling of the key by a mechanical mechanism, the number of parts of the keyboard device increases and the structure becomes complicated. Also, with this keyboard device, the touch feeling of the key is changed only by changing the range in which the key receives the reaction force from the weight, so the touch feeling can be changed only with a predetermined part of the key stroke range. . Therefore, it is not possible to finely adjust the touch feeling, such as changing the touch feeling in the entire key stroke, or changing the touch feeling by determining the range within the key stroke.

  On the other hand, in the keyboard device described in Patent Document 2, the touch feeling of the key is adjusted by feedback control based on the detection result of the key operation by the sensor. Can be performed. However, in this keyboard apparatus, since it is necessary to install a magnet and a coil corresponding to each key, the number of parts of the keyboard apparatus increases and the structure becomes complicated, as in the keyboard apparatus of Patent Document 1. In addition, the weight of the keyboard device increases as the number of parts increases. Furthermore, since many coils are provided, there is a problem that the power consumption of the keyboard device is increased.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a keyboard device capable of adjusting the touch feeling of a key to an arbitrary touch feeling with a simple and lightweight structure.

  In order to solve the above-described problems, a keyboard device of the present invention includes a key that is swingably supported, and a reaction force generation unit that generates a reaction force against a key pressing operation. It is characterized by comprising an electroactive polymer made of an elastic material that is deformed by the application of.

  According to this configuration, a keyboard device that can generate a reaction force against the key press with a simple and lightweight structure and can adjust the touch feeling of the key to an arbitrary touch feeling. That is, since the electroactive polymer is used for the reaction force generating means, mechanical components as the reaction force generating means such as the keyboard device described in Patent Document 1 or Patent Document 2 are not required. The structure of the generating means can be simplified and the weight can be reduced. On the other hand, by deforming the electroactive polymer by applying a voltage, the reaction force generated by the electroactive polymer is changed to set the reaction force (feeling of resistance to playing) to an arbitrary reaction force. Will be able to. When no voltage is applied to the electroactive polymer, the electroactive polymer functions as a normal elastic body. Even in this case, it is possible to generate a constant reaction force against the key depression.

  In the above keyboard device, the electroactive polymer may be provided so as to be physically deformed when the key is in the non-pressed position.

  According to this configuration, when the key is in the non-pressed position, the electroactive polymer is subjected to a pressure (load) due to physical deformation. Therefore, since the reaction force against this pressure is applied to the key from the electroactive polymer, it is possible to support the key in a stable state at the non-pressed position.

  Further, according to this configuration, a voltage is applied to the electroactive polymer by setting the pressurization due to physical deformation applied to the electroactive polymer to an appropriate pressure when the key is in the non-key-pressing position. It is possible to prevent the key from being moved due to the deformation of the electroactive polymer when the voltage is applied or when the application of the voltage is stopped, and it is possible to effectively prevent the key from being displaced at the non-key pressed position.

  In the keyboard device, the command value output means for outputting the command value of the voltage applied to the electroactive polymer, and the voltage is applied to the electroactive polymer based on the command value output from the command value output means. Reaction force control means for controlling the reaction force generated in the active polymer.

  According to this configuration, since the reaction force generated in the electroactive polymer can be arbitrarily set by the command value output means and the reaction force control means, the touch feeling of the key can be adjusted to any touch feeling. .

  Further, the keyboard device includes a key operation detecting unit that detects a key operation, and the command value output unit is configured to detect a voltage applied to the electroactive polymer based on the key operation detected by the key operation detecting unit. The command value may be output.

  According to this configuration, the reaction force generated in the electroactive polymer can be set based on the key motion detected by the key motion detecting means, so that the touch feeling of the key can be adjusted according to the actual key motion. Is possible.

  In addition, the above keyboard device has a control pattern table storing a plurality of control patterns related to key operation control, and based on the key operation detected by the key operation detecting means, any control is performed from the control pattern table. A reaction force information output means for selecting a pattern and outputting reaction force information generated by the electroactive polymer based on the selected control pattern is provided, and the command value output means is generated by the electroactive polymer. It has a voltage command value table storing a plurality of voltage command values corresponding to a plurality of reaction forces, selects one of the voltage command values from the voltage command value table based on the output of the reaction force information output means, and selects the voltage command value table. The voltage command value thus output may be output to the reaction force control means.

  According to this configuration, it is possible to prepare a plurality of control patterns related to the key operation in advance and control the key operation based on the control pattern selected from them. Therefore, various key touch feelings can be realized based on factors such as the type and tone color of musical sound generated by the electronic musical instrument and information input from the operation panel of the electronic musical instrument.

  According to the keyboard device of the present invention, the touch feeling of the key can be adjusted to an arbitrary touch feeling with a simple and lightweight structure.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, among the two sides in the longitudinal direction of the keys provided in the keyboard device, the player side playing the keyboard is referred to as the front or the front, and the opposite side is referred to as the back or the rear.

[First Embodiment]
FIG. 1 is a diagram showing a configuration example of a key 10 provided in the keyboard device 1 according to the first embodiment of the present invention, and is a schematic side sectional view showing the key 10 and its surrounding components. In the figure, one key 10 provided in the keyboard device 1 and its peripheral components are shown. The keyboard device 1 includes a bottom plate 2, a frame 3 attached to the bottom plate 2, a key 10 supported to be swingable with respect to the frame 3, and an electroactive polymer 20 provided between the key 10 and the frame 3. And is configured. Although FIG. 1 shows a case where the key 10 is a white key, the configuration is the same in the case of a black key.

  The bottom plate 2 is a substantially flat plate member that constitutes a shelf plate on which the keys 10 are arranged and a bottom portion of the case. The frame 3 is installed on the upper surface side of the bottom plate 2, and includes a rear surface portion 3 a extending in the vertical direction in the vicinity of the rear portion of the keyboard device 1, and horizontally protruding forward from the rear surface portion 3 a in the middle of the key 10 in the front-rear direction. The flat surface portion 3b extending to the position and the front surface portion 3c extending downward from the lower surface near the front end of the flat surface portion 3b are integrally formed, and the lower end of the rear surface portion 3a and the lower end of the front surface portion 3c are fixed on the bottom plate 2. Has been. The bottom plate 2 and the frame 3 extend in the scale direction of the keyboard device 1 (a direction orthogonal to the paper surface of FIG. 1) and are disposed across positions corresponding to the plurality of keys 10.

  The key 10 is supported by a key support piece 4 provided on the upper front side of the rear surface portion 3 a of the frame 3. The rear end of the key 10 is pivotally supported by a key fulcrum 5 provided on the key support piece 4, and the front side is swingable up and down around the key fulcrum 5. A flat panel 6 is attached above the rear side of the key 10. The panel 6 is supported by the upper end of the rear surface portion 3a of the frame 3 and the upper end of a side plate (not shown) that constitutes both ends of the keyboard device 1, and projects horizontally to the front side. The panel 6 also extends in the scale direction of the keyboard device 1 and is disposed across positions corresponding to the plurality of keys 10. A stopper 7 is provided on the lower surface side of the front end of the panel 6. The stopper 7 abuts on the upper surface of the key 10 at the non-key-pressing position shown in FIG. 1, and restricts the key 10 from rotating upward from the non-key-pressing position.

  The front end of the bottom plate 2 extends to a position directly below the front end of the key 10, and a protruding portion 2 a that protrudes upward toward the key 10 is provided at that position. A key switch 8 is installed on the upper surface of the overhang portion 2a. The key switch 8 is turned on by being pressed by the lower surface of the key 10 when the key 10 is lowered by pressing the key. Further, a drive piece 11 projecting downward is formed at a position behind the key switch 8 on the lower surface of the key 10. The drive piece 11 is disposed in the gap between the front surface portion 3 c of the frame 3 and the protruding portion 2 a of the bottom plate 2. At the lower end of the drive piece 11, a projecting fixing portion 11 a that protrudes horizontally toward the rear side is formed. On the other hand, the front end of the flat surface portion 3b of the frame 3 is a protruding fixing portion 3d that protrudes horizontally from the front surface portion 3c toward the front side. The fixing part 3d of the frame 3 and the fixing part 11a of the key 10 are arranged at positions facing each other with a predetermined interval in the vertical direction.

  An electroactive polymer 20 is attached between the fixed portion 3d and the fixed portion 11a. The electroactive polymer 20 is a member that functions as a reaction force generating unit that generates a reaction force against a key pressing operation of the key 10. Further, in the keyboard device 1, as a means for applying a voltage to the electroactive polymer 20, although not shown in the drawings, a power source and a voltage from the power source are applied to the electroactive polymer 20 to be electrically activated. A controller for driving the polymer 20 is provided.

  The electroactive polymer 20 is made of an elastic material having a structure to be described later, and is formed in a rectangular thin plate shape (film shape). One end in the longitudinal direction is fixed to the fixing portion 3d of the frame 3, and the other end is a key. 10 fixed portions 11a. As means for fixing the electroactive polymer 20 to the fixing portion 3d or the fixing portion 11a, adhesion by an adhesive or caulking (including heat caulking) is used.

  A moment (rotational moment) is applied to the key 10 in the clockwise direction shown in FIG. Since the key 10 to be moved downward by this moment is supported by the electroactive polymer 20, the electroactive polymer 20 is stretched by being pulled at the non-key-pressing position shown in FIG. Therefore, at the non-key-pressing position, the electroactive polymer 20 is under a pressure (load) applied by pulling, and the self-weight of the key 10 and the reaction force applied to the key 10 from the electroactive polymer 20 (with respect to the pressure) The key 10 is supported in a stationary state by a balance between the reaction force and the reaction force from the stopper 7. As described above, the electroactive polymer 20 is provided in a state of being physically deformed by the force applied from the key 10 when the key 10 is in the non-key-pressed position.

  2A and 2B are diagrams for explaining the structure of the electroactive polymer 20, wherein FIG. 2A shows a state when no voltage is applied to the electroactive polymer 20, and FIG. 2B shows a state where voltage is applied. It is a figure which shows the state at the time. The electroactive polymer 20 has a structure in which an insulating film 22 is sandwiched between two electrode films 21 and 21. For example, a film made of conductive silicon resin having a thickness of several tens of μm is used for the electrode film 21, and a film made of insulating silicon resin having a thickness of several tens of μm is used for the insulating film 22, for example. In this electroactive polymer 20, when a potential difference is applied to the two electrode films 21, 21, the insulating films 22 are compressed in the thickness direction by bringing both electrode films 21, 21 closer by electrostatic force. As a result, the electrode films 21 and 21 and the insulating film 22 extend in the vertical and horizontal directions, and the area thereof is increased. Since the electrode films 21 and 21 and the insulating film 22 are made of an elastic material, the electroactive polymer 20 functions as a normal elastic body even when no voltage is applied to the electroactive polymer 20.

Here, the reaction force applied to the key 10 from the electroactive polymer 20 when the electroactive polymer 20 has the following structure and dimensions will be considered. Hereinafter, a case where the nominal stress of the electroactive polymer 20 changes linearly will be considered.
Number of layers: 1 layer Elastic modulus: E = 0.5 GPa
Width: h = 10 mm Thickness: t = 0.05 mm Initial length (natural length): l ₀ = 30 mm
In this case, if the cross-sectional area A, stress σ, and strain ε of the electroactive polymer 20 are given, the relationship between the pressurizing force F applied to the electroactive polymer 20 and the total length l (or elongation l−l ₀ ) is as shown in (Equation 1). .

  If the deformation amount (elongation amount) with respect to the natural length in the longitudinal direction of the electroactive polymer 20 at the non-key-pressing position is 20 mm, the pressure applied to the electroactive polymer 20 in this state is 0.170 kg from (Equation 1). Become. The pressure obtained by subtracting the weight of the key 10 from this pressure is a reaction force applied to the finger from the key 10 when the key 10 is started to be pressed in a state where no voltage is applied to the electroactive polymer 20.

  On the other hand, when the electroactive polymer 20 is deformed (extended) by 10 mm in the longitudinal direction by applying a voltage to the electroactive polymer 20 at the non-key-pressing position, the entire elongation of the electro-active polymer 20 at the non-key-pressing position. If the amount remains 20 mm, the amount of deformation (elongation) of the electroactive polymer 20 due to the pressure applied from the key 10 is 10 mm. In this state, the pressure applied to the electroactive polymer 20 is 0.085 kg. A value obtained by subtracting the weight of the key 10 from this pressure is a reaction force applied to the finger from the key 10 when the key 10 is started to be pressed in a state where a voltage is applied to the electroactive polymer 20.

  In this way, since the electroactive polymer 20 is stretched by application of a voltage, the pressure applied to the electroactive polymer 20 is reduced, and accordingly, the reaction force applied to the finger from the key 10 when the key 10 is started to be pressed is increased. Can be small. That is, the touch feeling of the key 10 can be reduced by applying a voltage to the electroactive polymer 20. Therefore, in the keyboard device 1 of the present embodiment, it is possible to arbitrarily set the touch feeling of the key 10 by applying a voltage to the electroactive polymer 20 during performance. It should be noted that the pressure applied to the electroactive polymer 20 here is the electric activity between the key 10 and the frame 3 even when the electroactive polymer 20 is stretched by applying a voltage to the electroactive polymer 20 at the non-key-pressed position. The pressure is set such that the length of the polymer 20 does not change and the key 10 does not move (the support of the key 10 does not become unstable).

  Assuming that no pressure is applied to the electroactive polymer 20 at the non-key-pressed position, the force for returning the key 10 to the non-key-pressed position when the key 10 is released is weakened. Alternatively, the speed of returning the key 10 to the non-key-pressed position is slow. Further, when a voltage is applied to the electroactive polymer 20, the electroactive polymer 20 stretches and loosens, and the support of the key 10 becomes unstable, or the key 10 moves from a non-key-pressed position and the position is shifted. Or Therefore, as described above, it is desirable to install the electroactive polymer 20 in a state where the key 10 is in the non-key-pressed position and apply pressure to the electroactive polymer 20.

  In the present embodiment, the case where only the electroactive polymer 20 is provided as the reaction force generating means for generating the reaction force against the key pressing operation has been described. However, as the reaction force generating means provided in the keyboard device of the present invention, It is possible to add another reaction force generating means to the electroactive polymer 20. As an example, although not shown, the electroactive polymer 20 can be attached between the key 10 and the frame 3, and another elastic body such as a spring or rubber can be attached. Thereby, the reaction force with respect to the key depression can be generated by using the electroactive polymer 20 and another elastic body in combination. Even in this case, the touch feeling of the key 10 can be changed by applying a voltage to the electroactive polymer 20 to change the magnitude of the reaction force against the key depression.

  Further, in the present embodiment, the case where the electroactive polymer 20 is formed in an elongated film shape (thin plate shape) is shown, but the electroactive polymer 20 can be formed in a shape other than the film shape. As an example, it may be formed in a cylindrical shape such as a rod shape, a string shape, or a cylindrical shape. Further, the number of layers of the electroactive polymer 20 is not limited to one layer, and a laminated structure of two or more layers can be formed according to the magnitude of the reaction force generated in the electroactive polymer 20.

Here, with reference to FIG.3 and FIG.4, the key pressing force (key pressing force) in the keyboard apparatus 1 of this embodiment is considered. FIGS. 3 and 4 are schematic diagrams showing the operation of the key 10 when no voltage is applied to the electroactive polymer 20 and when a voltage is applied, respectively. First, consider the case where no voltage is applied to the electroactive polymer 20 shown in FIG. In the same figure, (a) shows a natural length state in which no external force acts on the electroactive polymer 20, and (b) shows that the electroactive polymer 20 is pressurized (stretched) and attached to the key 10. (C) shows a state in which the key 10 is pressed down. Where, F: key pressing force (reaction force against key pressing), I: key moment of inertia, M: key mass, a: distance between key fulcrum and center of gravity, b: key fulcrum and fixed position of electroactive polymer , C: distance between the key fulcrum and the key pressing position, g: gravitational acceleration, k: elastic modulus of the electroactive polymer, x: deformation amount of the electroactive polymer due to key pressing, x ₀ : electric activity due to pressure The amount of deformation of the polymer, θ: the amount of rotation of the key by pressing the key, θ ₀ : the amount of rotation of the key by pressing, and the equation of motion of the key 10 in this case is given by the following (Equation 2). The key pressing force F obtained from the equation (3) is as follows.

Next, consider the case where a voltage is applied to the electroactive polymer 20 shown in FIG. In the figure, (a) shows a state of natural length in which no external force is applied to the electroactive polymer 20 and a state in which no voltage is applied to the electroactive polymer 20, and (b) shows a natural length. (C) shows a state in which a voltage is applied to the electroactive polymer 20, and (c) shows a state where the electroactive polymer 20 to which a voltage is applied is pressurized (stretched) and attached to the key 10. The state in which the key 10 is pressed down while a voltage is applied to the electroactive polymer 20 is shown. Where x _{e is} the deformation amount of the electroactive polymer due to voltage application, x ₀ ′ is the deformation amount of the electroactive polymer due to pressurization during voltage application, θ ₀ ′ is the key rotation amount due to pressurization during voltage application, Then, the equation of motion of the key 10 in this case becomes (Equation 4) below, and the key pressing force F ′ obtained from this equation of motion becomes (Equation 5) below.

（式６）から明らかなように、電気活性ポリマ２０に電圧を印加すると、電圧を印加しない場合よりも鍵１０を押す力（鍵１０から指にかかる反力）が小さくなる。 From (Expression 3) and (Expression 5), the following (Expression 6) is derived.

As apparent from (Equation 6), when a voltage is applied to the electroactive polymer 20, the force pressing the key 10 (reaction force applied from the key 10 to the finger) is smaller than when no voltage is applied.

[Second Embodiment]
Next, a keyboard apparatus according to a second embodiment of the present invention will be described. In the description of the second embodiment and the corresponding drawings, the same or corresponding components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted below. In addition, matters other than those described below are the same as those in the first embodiment. The same applies to other embodiments.

  FIG. 5: is a schematic side view which shows the key 10 with which the keyboard apparatus 1-2 concerning 2nd Embodiment of this invention is provided, and its surrounding component parts, (a) is the state which has the key 10 in a non-key-pressing position. FIG. 5B is a diagram illustrating a state where the key 10 is pressed. In the keyboard device 1 of the first embodiment, the electroactive polymer 20 is attached between the key 10 and the frame 3, and the electroactive polymer 20 is pulled in the longitudinal direction by pressing the key. In the keyboard device 1-2, the mounting structure of the electroactive polymer 20 is changed so that the surface of the electroactive polymer 20 is pressed by the key.

  That is, in the keyboard device 1-2, the drive piece 12 for pressing the electroactive polymer 20 is formed on the lower surface of the key 10. The drive piece 12 is formed as a shaft-like protrusion that protrudes downward. The electroactive polymer 20 is arranged in a film shape (diaphragm shape) with its outer periphery fixed to the frame 3 or the bottom plate 2 on the lower side of the driving piece 12, and the upper surface is installed facing the lower end of the driving piece 12. ing. In this embodiment as well, when the key 10 is in the non-key-pressing position, the driving piece 12 comes into contact with and presses the electroactive polymer 20 due to its own weight. Therefore, the electroactive polymer 20 is installed in a state where it is pressurized by the key 10 (a state where it is pressed and stretched).

  As shown in FIG. 5B, the electroactive polymer 20 is stretched by the driving piece 12 as the key 10 is moved by pressing the key. At this time, by applying a voltage to the electroactive polymer 20, the reaction force applied to the finger from the key 10 when the key 10 is started to be pressed is reduced as in the first embodiment, and the touch feeling of the key 10 is reduced. Can be lightened.

[Third Embodiment]
Next, a keyboard apparatus according to a third embodiment of the present invention will be described. In the keyboard device 1 of the first embodiment or the keyboard device 1-2 of the second embodiment, the voltage applied to the electroactive polymer 20 during performance is constant, and the touch feeling of the key 10 is changed during the key pressing operation. It never happened. On the other hand, in the third embodiment, the operation of the key 10 is detected during the key pressing operation, and the voltage applied to the electroactive polymer 20 is changed based on the detected operation to change the touch feeling of the key 10. It is configured so that it can.

  FIG. 6 is a block diagram illustrating a configuration of the control mechanism 30 provided in the keyboard device 1-3 according to the present embodiment. The control mechanism 30 includes a main control unit (CPU) 31, a RAM 32, a ROM 33, an operation unit 34, and a display unit 35. The operation unit 34 includes an operation panel (not shown) of an electronic musical instrument provided with the keyboard device 1-3. The display unit 35 is composed of a display panel (not shown) of an electronic musical instrument provided with the keyboard device 1-3.

  In addition, the control mechanism 30 includes key operation detection means 40 that detects the operation of the key 10 by pressing the key. The key motion detection means 40 includes a key displacement detector 41 that detects the displacement of the key 10, a key speed detector 42 that detects the speed of the key 10, and a key acceleration detector 43 that detects the acceleration of the key 10. . Detection signals from the key displacement detection unit 41, the key speed detection unit 42, and the key acceleration detection unit 43 are converted into digital signals by the A / D conversion units 44, 45, and 46, respectively, and input to the CPU 31. . 6 shows a case where the key movement detecting means 40 includes a key displacement detecting unit 41, a key speed detecting unit 42, and a key acceleration detecting unit 43. However, only the displacement of the key 10 or the displacement and speed of the key 10 are shown. However, the key speed detector 42 and the key acceleration detector 43 are not necessarily provided.

  For the key displacement detection unit 41, a displacement sensor including a Hall element can be used. Although not shown, the displacement sensor includes a magnet attached to the key 10 and a hall element attached to the frame 3 at a position facing the magnet. In this displacement sensor, the magnetism incident on the Hall element from the magnet changes due to the change in the distance between the magnet and the Hall element due to the movement of the key 10, and the output of the Hall element changes. Therefore, by measuring the output of the hall element, the distance between the magnet and the hall element can be calculated and the displacement of the key 10 can be detected.

  Further, as another example of the key displacement detection unit 41, a displacement sensor having a gray scale can be used. Although not shown, the displacement sensor includes a gray scale attached to the key 10, and a light emitting element and a light receiving element installed at a position facing the gray scale in the frame 3. In this displacement sensor, light that is emitted from the light emitting element and transmitted or reflected through the gray scale is received by the light receiving element. At this time, since the amount of light received by the light receiving element is changed by the movement of the key 10 by pressing the key, the displacement of the key 10 can be detected based on the output of the light receiving element. In addition to installing the light emitting element and the light receiving element at a position facing the gray scale, the optical fiber is extended from the light emitting element and the light receiving element installed at other positions, and the tip of the optical fiber is directed to the gray scale. You may arrange.

  As the key speed detection unit 42, a speed sensor including a coil and a magnet can be used. Although not shown, the speed sensor includes a magnet attached to the key 10 and a coil attached to the frame 3 at a position facing the magnet. In this speed sensor, the magnetic flux passing through the inside of the coil is changed by the movement of the key 10 by pressing the key, and an electromotive force is generated in the coil. The speed of the key 10 can be detected by measuring the electromotive force of the coil.

  Further, as another example of the key speed detection unit 42, an angular speed sensor including a MEMS (Micro Electro Mechanical Systems) gyroscope can be used. Although not shown, this angular velocity sensor is configured by attaching a MEMS gyroscope to the key 10. By measuring the angular velocity of the key 10 that rotates around the key fulcrum 5 with this MEMS gyroscope, the instantaneous velocity of the key 10 can be detected.

  As the key acceleration detection unit 43, a MEMS angular acceleration sensor can be used. Although not shown, the MEMS angular acceleration sensor can be used by being attached to the key 10. By measuring the angular acceleration of the key 10 that rotates about the key fulcrum 5 with this MEMS angular acceleration sensor, the acceleration of the key 10 can be detected.

  On the other hand, the ROM 33 stores a control pattern table 36 and an actuator output table (voltage command value table) 37. FIG. 7 is a conceptual diagram of the control pattern table 36 and the actuator output table 37. The control pattern table 36 shown in FIG. 6A is a table storing a control pattern for generating a touch feeling of the key 10 according to the key operation (displacement, speed, acceleration), and corresponds to the key operation. Many patterns of reaction force (actuator output) generated by the electroactive polymer 20 are stored. The actuator output table 37 shown in FIG. 5B is a table that stores a large number of patterns of command values (voltage ratios of PWM signals in PWM drive) applied to the electroactive polymer 20 corresponding to actuator outputs. .

  The control pattern table 36 and the CPU 31 constitute reaction force information output means 60 that outputs information of reaction force generated by the electroactive polymer 20. The actuator output table 37 and the CPU 31 constitute command value output means 70 that outputs a voltage command value based on the reaction force information from the reaction force information output means 60.

  The operation unit 34 is used to input control pattern settings to be referred to from the control pattern table 36. The display unit 35 is used for displaying the set control pattern. Note that the operation unit 34 and the display unit 35 are also used to perform other settings and display including settings and display of types and tone colors of musical sounds generated by the electronic musical instrument including the keyboard device 1-3.

  Further, the keyboard device 1-3 includes a controller 50 that drives the electroactive polymer 20 by applying a voltage to the electroactive polymer 20. The controller 50 applies a voltage to the electroactive polymer 20 based on the command value of the voltage referred from the actuator output table 37 (the duty ratio of the PWM signal in the PWM drive), and generates a reaction in the electroactive polymer 20. It controls force and functions as reaction force control means.

  A procedure for adjusting the touch feeling of the key 10 in the keyboard device 1-3 having the above configuration will be described. FIG. 8 is a flowchart for explaining this procedure. First, it is determined whether or not the touch setting of the key 10 is input from the operation unit 34 (step ST1). When the setting of the touch feeling of the key 10 is input, the displacement (x) of the key 10 is detected by the key displacement detection unit 41 according to the movement of the key 10 by the key pressing operation (step ST2). Further, the key speed detector 42 detects the moving speed (v) of the key 10 (step ST3). Further, the key speed detection unit 42 detects the acceleration (a) of the key 10 (step ST4). If only the displacement (x) of the key 10 or only the displacement (x) and speed (v) of the key 10 is detected, the steps ST3 and ST4 can be omitted.

  Subsequently, the reaction force information output unit 60 is referred to from the control pattern table 36 based on the touch feeling input from the operation unit 34 and the operation of the key 10 detected in steps ST2 to ST4. Is selected, and based on the selected control pattern, information on the reaction force (actuator output) generated by the electroactive polymer 20 is output (step ST5). The command value output means 70 selects any voltage command value (PWM signal duty ratio) referenced from the actuator output table 37 based on the reaction force information from the reaction force information output means 60 (step ST6). The selected voltage command value is output to the controller 50. (Step ST7). Based on this voltage command value, the controller 50 applies a voltage to the electroactive polymer 20 to control the reaction force generated in the electroactive polymer 20 (step ST8). In this way, when the electroactive polymer 20 is deformed by the application of voltage, the reaction force applied to the key 10 from the electroactive polymer 20 changes, and the touch feeling of the key 10 is changed. Thereafter, when it is necessary to continuously detect the operation of the key 10 and adjust the touch feeling based on the touch feeling setting input from the operation unit 34, the process returns to step ST2 and the procedure after step ST2 is performed ( Step ST9).

  According to the keyboard device 1-3 of the present embodiment, the operation of the key 10 is detected by the key operation detecting means 40, and a voltage is applied to the electroactive polymer 20 based on the detected operation, so that the key pressing operation is in progress. Thus, the touch feeling of the key 10 can be changed in various patterns. For example, while the key 10 is depressed, a voltage is applied to the electroactive polymer 20 so that the key 10 can be pressed with a light force, and when the key 10 returns to the non-pressed position, it is applied to the electroactive polymer 20. The voltage can be turned off to quickly return the key 10 to the non-key pressed position. Further, if the voltage applied to the electroactive polymer 20 is changed while the key 10 is depressed, the reaction force applied from the key 10 to the finger can be changed even while the key 10 is depressed.

また、電気活性ポリマへの印加電圧をＶとすると、（式８）に示すようになる。

（式７）及び（式８）から明らかなように、電気活性ポリマ２０への印加電圧を変化させることで、押鍵に対する反力（演奏抵抗感）を任意に設定することが可能となる。 Here, a change in the resistance to performance due to the application of voltage to the electroactive polymer 20 in the keyboard device 1-3 of the present embodiment will be considered. Again, considering the model shown in FIGS. 3 and 4, the following (Expression 7) is derived from the above (Expression 3) and (Expression 5).

Further, assuming that the voltage applied to the electroactive polymer is V, it is as shown in (Equation 8).

As is clear from (Equation 7) and (Equation 8), it is possible to arbitrarily set the reaction force (performance resistance) against the key depression by changing the voltage applied to the electroactive polymer 20.

  Next, an example of setting a touch feeling (performance resistance feeling) in the keyboard device 1-3 according to the present embodiment will be described. FIG. 9 is a graph showing the relationship between the displacement of the key during key depression and key release and the reaction force applied to the finger pushing the key in a conventional grand piano. In the graph of the figure, the horizontal axis represents the key displacement from the non-key-pressed position, and the vertical axis represents the reaction force applied to the finger. In the example shown in the figure, the reaction force applied to the finger when the key is moved slowly at a constant speed is measured, and the measurement points are connected in a curved line. Since a grand piano has a structure in which a damper, a hammer, and the like are sequentially moved by a moving key, as shown in the figure, the reaction force applied from the key to the finger is not constant, and changes as the key moves. Therefore, the touch feeling of the key greatly changes during the key pressing operation.

  Therefore, in the keyboard device 1-3 of the present embodiment, if the reaction force generated in the electroactive polymer 20 is changed according to the graph of FIG. 9, it is possible to obtain a touch feeling similar to that of a grand piano. Become. If this touch feeling control pattern is stored in the control pattern table 36, the player can easily realize the touch feeling of the key 10 similar to a grand piano by selecting the control pattern on the operation unit 34. become.

  In the example shown in FIG. 9, the reaction force distribution when the key is slowly moved at a constant speed on the grand piano is shown. However, when the key is moved fast or the speed is changed, The reaction force distribution is different from the example shown in FIG. Therefore, even when setting the touch feeling imitating the touch feeling of the same grand piano, the reaction force control pattern differs depending on the key speed by the key depression. Therefore, it is necessary to store a large number of control patterns based on key operations in the control pattern table 36.

  Note that the setting of the touch feeling of the key 10 is merely an example, and the keyboard device 1-3 according to the present embodiment can change the touch feeling of the key 10 with various settings other than the above. For example, in addition to the grand piano, it is possible to set a touch feeling imitating the performance resistance of other keyboard devices such as an organ. In addition, the control pattern table is referred to according to the age of the performer input by the operation unit or the skill level information of the keyboard instrument, and the key touch adapted to the player's age and skill level is referred to. It is also possible to realize a feeling.

  As described above, according to the keyboard devices 1 to 1-3 according to the embodiments of the present invention, since the electroactive polymer 20 is used as the reaction force generating means for generating the reaction force against the key pressing operation, it is simple and lightweight. The touch feeling of the key 10 can be adjusted to an arbitrary touch feeling with a simple structure. In particular, since the electroactive polymer 20 is lighter in weight and simpler in structure than a solenoid or the like, the keyboard device can be significantly reduced in weight and simplified as compared with the conventional one.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible. It should be noted that any shape, structure, or material not directly described in the specification and drawings is within the scope of the technical idea of the present invention as long as the effects and advantages of the present invention are exhibited.

  For example, the number and positions of the electroactive polymers 20 that are the reaction force generating means are not limited to those shown in the above embodiment, and a plurality of electroactive polymers 20 can be installed. It can also be installed in a position. In addition, the specific shape and structure of the electroactive polymer 20 shown in the above embodiment are merely examples, and the electroactive polymer 20 may have other shapes and structures.

  Moreover, in the keyboard apparatus 1-3 of 3rd Embodiment, although the case where a displacement sensor, a speed sensor, and an acceleration sensor were provided as the key motion detection means 40 was demonstrated, as the key motion detection means 40, besides this, It is also possible to install a plurality of switches that are turned on or off in stages as the key 10 is moved by pressing the key. According to this configuration, the key displacement is detected by detecting the on / off state of a plurality of switches when a key is pressed or released, and the timing (time) at which the plurality of switches are sequentially turned on or off is detected. By doing so, the speed of the key 10 can be detected.

It is a figure which shows the structural example of the keyboard apparatus concerning 1st Embodiment of this invention. It is a figure for demonstrating the structure of an electroactive polymer. It is a figure which shows operation | movement of the key when not applying a voltage to an electroactive polymer. It is a figure which shows operation | movement of the key in the case of applying a voltage to an electroactive polymer. It is a figure which shows the structural example of the keyboard apparatus concerning 2nd Embodiment of this invention. It is a block diagram which shows the structure of the control mechanism with which the keyboard apparatus concerning 3rd Embodiment of this invention is provided. It is a conceptual diagram of a control pattern table and an actuator output table. It is a flowchart for demonstrating the procedure which adjusts the touch feeling of a key. It is a graph which shows the relationship between the displacement of the key in the conventional grand piano, and the reaction force applied to the finger which pushes a key.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Keyboard apparatus 2 Bottom plate 3 Frame 4 Key support piece 5 Key fulcrum 6 Panel 7 Stopper 8 Key switch 10 Key 11 Drive piece 12 Drive piece 20 Electroactive polymer (reaction force generating means)
21 Electrode film 22 Insulating film 30 Control mechanism 34 Operation unit 35 Display unit 36 Control pattern table 37 Actuator output table (voltage command value table)
40 Key Movement Detection Unit 41 Key Displacement Detection Unit 42 Key Speed Detection Unit 43 Key Acceleration Detection Unit 44 A / D Conversion Unit 45 A / D Conversion Unit 46 A / D Conversion Unit 50 Controller (Reaction Force Control Unit)
60 Reaction force information output means 70 Command value output means

Claims (5)

A key that is pivotably supported;
Reaction force generating means for generating a reaction force against the key pressing operation of the key,
The keyboard device, wherein the reaction force generating means includes an electroactive polymer made of an elastic material that is deformed by application of a voltage.   The keyboard device according to claim 1, wherein the electroactive polymer is provided so as to be physically deformed when the key is in a non-key-pressed position. Command value output means for outputting a command value of a voltage applied to the electroactive polymer;
Reaction force control means for controlling a reaction force generated in the electroactive polymer by applying a voltage to the electroactive polymer based on the command value output from the command value output means;
The keyboard device according to claim 1, further comprising: A key operation detecting means for detecting the operation of the key;
4. The keyboard apparatus according to claim 3, wherein the command value output means outputs a command value of a voltage to be applied to the electroactive polymer based on the operation of the key detected by the key action detection means. . A control pattern table storing a plurality of control patterns relating to the operation control of the key, and selecting one of the control patterns from the control pattern table based on the operation of the key detected by the key operation detecting means; And a reaction force information output means for outputting information of reaction force generated in the electroactive polymer based on the selected control pattern,
The command value output means has a voltage command value table storing a plurality of voltage command values corresponding to a plurality of reaction forces generated by the electroactive polymer, and based on the output of the reaction force information output means 5. The keyboard apparatus according to claim 4, wherein one of the voltage command values is selected from a voltage command value table, and the selected voltage command value is output to the reaction force control means.

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