JPH075877A - After touch sensor for electronic musical instrument - Google Patents

Abstract

PURPOSE:To provide an after touch sensor small in the differences among the outputs of pressure sensitive parts caused by the difference in the area of each key in contact with an after sensor for every key and the difference between a single tone playing and a chord playing and capable of obtaing more uniform after touch effect. CONSTITUTION:An after touch sensor 1 is provided in a keyboard device K of electronic keyboard instruments such as conventional electronic organs or pianos, placed under a keyboard 2 which consists of a white key 3 and a black key 5 and fixed on a chassis 10 of the bottom plate. The after touch sensor 1 is constructed by laminating and pasting together a felt 11 whose thickness is 1.0mm, a pressure reducing member 13 which is made of a polycarbonate plate (0.5mm thick), a pressure sensing section 15 and a shock absorbing member 17 which consists of a both surface cushion tape (0.5mm thick) on a reinforcing member 19 which consists of a stainless steel plate (SUS 301: 0.3mm thick).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aftertouch sensor which is provided in a keyboard device of an electronic musical instrument and detects an aftertouch when a key is pressed.

[0002]

2. Description of the Related Art Conventionally, electronic keyboard musical instruments such as electronic pianos and electronic organs have been widely used, but some keyboard devices of this type of electronic keyboard musical instrument include aftertouch (after normal key depression, There are some types in which various aftertouch effects can be applied to a musical sound being sounded, for example, by changing a pitch (pitch) or a volume according to a pressing force when the keyboard is pressed.

As shown in FIGS. 9 (a) and 9 (b), in this keyboard device K, a belt-shaped after-touch sensor P7 is provided below a keyboard P2 composed of a white key P3 and a black key P5.
(Hereinafter, referred to as an after sensor P7). As shown in the enlarged cross-sectional view of FIG. 9C, the after sensor P7 has a pressure sensitive portion P11 and a felt P13 stacked on the upper surface of a reinforcing member P9 such as an acrylic plate. Here, as the pressure-sensitive portion P11, for example, a sensor using a pressure-sensitive rubber, a pressure-sensitive conversion element (semiconductor sensor) such as disclosed in Japanese Patent Publication No. 2-49029, or the like, an output resistance value according to a pressing force is used. A sensor that changes is used.

Then, as shown by the chain double-dashed line in FIG. 9B, when after-touch is applied to the white key P3, the lower part P3a thereof comes into contact with the after-sensor P7 (the same applies to the black key P5). Therefore, in accordance with the pressing force F (that is, aftertouch), the pressing force is applied to the pressure sensitive portion P11 by the white key P3, and both terminals P11a and P11b of the pressure sensitive portion P11.
The resistance value changes (see FIG. 9A). Therefore,
If the change in the resistance value is detected by the detection circuit C, it is possible to apply various aftertouch effects such as changing the pitch and volume of a musical sound.

[0005]

However, in the conventional after-sensor P7, the following problems remain due to the characteristics of the pressure sensitive portion P11. That is, FIG.
As shown in (b), the lower part P3 of the white key P3 and the black key P5
a, P5a, due to various reasons, notches P3b, P5b
Are provided and their shapes are different. Therefore,
The white key P3 and the black key P5 may have different contact areas with the after sensor P7, which may cause a difference in the resistance value of the pressure sensitive portion P11. This is because, even when the pressure-sensitive portion P11 receives a constant load, the amount of change in the resistance value varies depending on the area that receives the load. If such a difference in resistance value occurs, the white key P3 and There is a problem that a uniform aftertouch effect cannot be obtained with the black key P5.

The following problems also remain. That is, compared to the case of playing a single note, there is a problem that when the chord is played by pressing a plurality of keys at the same time, the resistance value of the pressure-sensitive portion P11 changes greatly. This is because, in the case of playing a chord, the number of keys pressing the after-sensor P7 increases, and a larger total load is applied to the pressure-sensitive portion P11 in a larger area. If the difference in resistance value becomes large, the effect of aftertouch also becomes large, which hinders performance.

The present invention has been devised in order to solve the above-mentioned problems, and the resistance of the pressure-sensitive portion due to the difference in the contact area with the after sensor for each key and the difference between the single note performance and the chord performance. An object of the present invention is to provide an aftertouch sensor that has a small difference in output of values and can obtain a more uniform aftertouch effect.

[0008]

The invention according to claim 1 devised to solve the above-mentioned problems is provided below a keyboard composed of a plurality of keys, and is pressed by a key among the keys. An aftertouch sensor for an electronic musical instrument having a pressure-sensitive portion whose output changes according to pressure, wherein an upper surface side of the pressure-sensitive portion,
The gist of an aftertouch sensor for an electronic musical instrument is a load distribution member formed of a hard material and configured to distribute a load applied by the key.

According to a second aspect of the present invention, the pressure-sensitive portion is
The resistance value decreases non-linearly as the pressing force applied from the key in the key increases, and the rate of change has a pressure-resistance characteristic, and the plurality of keys are simultaneously pressed. The chordal resistance value of the pressure-sensitive portion is a pressure-sensitive portion which is the parallel sum of the resistance values of the respective keys, and by using the load distribution member, the resistance of the pressure-resistance characteristic of the pressure-sensitive portion is used. An aftertouch sensor for an electronic musical instrument according to claim 1, wherein a region having a large rate of change in value is used.

Further, the invention of claim 3 is characterized in that a cushioning member which deforms according to the shape of the load distributing member is provided on the upper surface and / or the lower surface of the load distributing member. The gist is the aftertouch sensor of the electronic musical instrument described in 2.

The invention according to claim 4 is the aftertouch sensor for an electronic musical instrument according to any one of claims 1 to 3, characterized in that a reinforcing member made of stainless steel is provided on a lowermost layer of the aftertouch sensor. And

Here, the pressure-sensitive portion is, for example, a pressure-sensitive conversion element (semiconductor sensor) disclosed in Japanese Patent Publication No. 2-49029, or pressure-sensitive rubber (for example, carbon black or metal particles in synthetic rubber). Mixed with the conductive particles of
Etc. can be used. Further, as the hard material forming the load distribution member, for example, polycarbonate,
Various materials such as a hard synthetic resin such as an acrylic resin and a hard vinyl chloride resin, a metal such as iron, and other inorganic materials can be used. The load distribution member is provided on the upper surface side of the pressure sensitive portion (the surface side that receives the pressing force from the key), and may be directly attached to the upper surface of the pressure sensitive portion. Alternatively, another member such as the cushioning member may be provided between them.

Further, as the buffer member, for example, a soft synthetic resin such as urethane rubber or soft vinyl chloride resin (or a foamed body thereof) can be used. Further, it is preferable to use a double-sided cushion tape (double-sided adhesive foam tape) made of any of these materials because the overall thickness of the aftertouch sensor can be reduced.

[0014]

In the aftertouch sensor according to the first aspect of the present invention, the load distribution member made of a hard material is provided on the upper surface side of the pressure sensitive portion. Therefore, the load applied by the key during key depression is dispersed through the load distribution member over a range wider than the contact area between the key and the after sensor and is transmitted to the pressure-sensitive portion. The influence on the output value of the pressure sensitive part due to the difference in the contact area is reduced,
A more uniform aftertouch effect can be obtained.

Further, in the after-touch sensor according to a second aspect of the present invention, in the pressure-sensitive section, the resistance value decreases non-linearly as the pressing force applied by the key being pressed increases, and the rate of change thereof decreases. -It has a resistance characteristic, and further has such a characteristic that the chord resistance value of the pressure sensitive portion when a plurality of keys are pressed simultaneously is the parallel sum of the resistance values of the respective keys.

Therefore, by dispersing the load applied to the pressure sensitive portion by using the load distribution member, the area where the rate of change of the resistance value is large as the usage area of the pressure-resistance characteristic without changing the resistance characteristic of the pressure sensitive portion. Can be used, and the difference between the resistance value when a single note is played and the resistance value that occurs in each key when a plurality of keys are pressed simultaneously (that is, when a chord is played) can be increased. Therefore, it is possible to bring the resistance value of the pressure sensitive portion during chord performance, which is the parallel sum of resistance values of the respective keys, close to the resistance value during single note performance.

The operation will now be described in more detail with reference to FIGS. 7 and 8. First, it is assumed that the pressure sensitive portion has a pressure-resistance characteristic (when a single key is depressed) as shown in the graph of FIG. Then, in the keyboard device equipped with the after sensor, the resistance value of the pressure-sensitive portion when a single key is pressed and the resistance value when a plurality of keys are pressed (that is, a chord is pressed) , It is ideal in terms of sensitivity to have a relationship as in the following equation (1). In other words, the ideal relationship between the expressions (1) is that in the case of chords, each key is usually loaded with a total load that is about twice that of a single note performance, and therefore the same resistance value as in the expression (1) is obtained. This is because the same degree of aftertouch effect can be obtained by setting so as to obtain.

(1) ... [resistance value (Ω) when a single key is pressed with a load X (g)] = [resistance value (Ω when three keys are pressed with a load 2X (g)] )] Next, as shown in FIG. 8A, a single key is pressed with a load X (g) to apply pressure P to the pressure-sensitive portion, and the resistance value is Y.
Suppose it has dropped to (Ω). On the other hand, as shown in FIG. 8B, when three keys are pressed with a total load of 2X (g), a load of 2X / 3 (g) is applied to the single key, and the pressure Pc is applied from each single key. The resistance value of each part receiving (= 2P / 3) is Yc
(Ω). Therefore, the resistance value of the entire pressure-sensitive portion is the parallel sum of the resistances of the three Yc (Ω), so that the resistance value Yc (Ω) of each key is 3Y ( Ω).

However, in the conventional after-sensor, since the load from the key is directly applied to the pressure sensitive portion through the felt, it is unavoidable to use the region of the characteristic curve shown in FIG. There wasn't. This is because if a region with a large rate of change in resistance value is used, the difference in output resistance value due to the influence of the contact area between the key and the after sensor becomes large, and uniform after-touch cannot be obtained. is there. Therefore, as shown in the graph of FIG. 7, the resistance value Y ′ (pressure P ′ applied to the pressure-sensitive portion) when a single key is pressed and the resistance of one key when three chords are pressed. The difference from the value Y'c (pressure Pc 'applied to the pressure-sensitive portion) was small, and it was not possible to satisfy the relationship of the above formula (1).

Therefore, in the present invention, by using the load distributing member, as shown in FIG. 7, the use area of the characteristic curve is not affected by the difference in the contact area between the key and the after sensor, and the resistance is maintained. It can be used by moving to an area where the value changes greatly. Therefore, the resistance value Y when the single key is pressed (pressure P applied to the pressure sensitive portion) and the resistance value Yc of one key when the chord of the three keys is pressed (pressure Pc ′ applied to the pressure sensitive portion) And the resistance value is Yc = 3
It can be approximated to Y, and can be approximated to the ideal relationship of the above-mentioned formula (1).

Further, in the after-touch sensor of the third aspect, since the cushioning member that deforms according to the shape of the load distribution member is provided on the upper surface and / or the lower surface of the load distribution member, each key of the keyboard is provided. It is possible to reduce variations in output values. That is, when the load distribution member has a shape distortion (for example, when there is unevenness such as a protrusion locally), the pressure-sensitive portion is strongly pressed locally, and the output value of each key of the keyboard varies. However, if a cushioning member is provided, it deforms according to the shape of the unevenness of the load distribution member,
The pressure sensitive portion is not strongly pressed locally, and the variation in the output value for each key is reduced.

Further, in the after-touch sensor according to the fourth aspect, the strength of the after-sensor can be maintained within a limited cross-sectional dimension (thickness) by using the reinforcing member made of stainless steel as the lowermost layer of the after-sensor. Since it is possible and is not easily plastically deformed, it does not adversely affect the pressure-sensitive portion. Moreover, since stainless steel is strong against rust, it does not adversely affect the pressure-sensitive portion.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, an aftertouch sensor 1 of the present embodiment (hereinafter referred to as aftersensor 1) is a keyboard device K of an electronic keyboard musical instrument such as a normal electronic organ or electronic piano.
Is provided below the keyboard 2 composed of the white key 3 and the black key 5, and is fixed to the chassis 10 at the bottom.

Here, as shown in the enlarged cross-sectional view of FIG. 1C, the after-sensor 1 is a stainless steel plate (SUS30).
1: a reinforcing member 19 made of 0.3 mm thick), a felt 11 having a thickness of 1.0 mm, a load distribution member 13 made of a polycarbonate plate (thickness of 0.5 mm), a pressure sensitive portion 15, and both sides. A cushioning member 17 made of cushion tape (thickness: 0.5 mm) is attached and stacked.

As the pressure sensitive portion 15, a pressure sensitive sensor (FSR) sold by Interlink (USA) is used. As shown in FIG. 2, the pressure sensitive portion (pressure sensitive sensor) 1
Reference numeral 5 is an elongated film-shaped sensor having a thickness of about 0.25 mm, and a first layer 15b in which an FSR polymer area (semiconductive pressure-sensitive layer) 15a is printed on a sheet such as mylar (polyethylene terephthalate), Two electrically isolated conductive cut lines 15c and 15d are superposed in a sandwich shape with a second layer 15e arranged facing each other. In addition, as shown in FIG.
f and 15g are connected to a detection circuit C (which is built in the electronic keyboard instrument) for detecting the resistance value. When the pressure (load) is applied on the FSR polymer area 15a in a constant area, the pressure-sensitive portion 15 has both cut lines 15c and 15c.
A closed circuit is formed between d and the resistance value between both terminals 15f and 15g decreases as shown in the pressure-resistance characteristic of FIG. Further, when a constant pressure is applied, the resistance value decreases as the contact area with the key increases.

The white key 3 and the black key 5 constituting the keyboard 2 are also included.
As shown in FIG. 3 (a perspective view of a part of the white key 3 and the black key 5 viewed from the lower side), the lower key is molded in a U-shaped cross section so that the lower parts 3a and 5a are opened. . Also, FIG.
As is clear from (b), the lower portions 3a and 5a are provided with notches 3b and 5b having different lengths. Therefore, the black key 5 is after the after-sensor 1 compared to the white key 3.
The contact area with is small. Although the keyboard 2 is shown only for one octave in FIG. 1A, it is actually 4
It has a range above the octave.

In the keyboard device K having the above-described structure, as shown in FIG. 1 (b), when the white key 3 is depressed and aftertouch is applied, the white key is indicated by a chain double-dashed line. The lower part 3a of 3 comes into contact with the after sensor 1, and the felt 1
The pressure-sensitive portion 15 is pressed via 1 and the load distribution member 13 (the same applies to the case of the black key 5). Then, the pressure sensitive portion 1 having the pressure-resistance characteristic (see FIG. 2B) as described above.
Since the electric resistance value between both terminals 15f and 15g of No. 5 is reduced, this change is detected by the detection circuit C, and aftertouch effect such as raising or lowering the pitch of the musical tone being sounded corresponding to the key being pressed. Take control.

Here, an experimental example showing the effect of the keyboard device 1 of this embodiment will be described. First, in Experimental Example 1, in the keyboard device K including the after sensor 1 of the embodiment,
(A) When a white key is pressed with a single key (that is, when a single note is played), (B) When three white keys are pressed simultaneously (that is, when a chord is played), (C) The black key is When the key was pressed with a single key, the relationship between the key pressing load and the resistance value of the pressure sensitive portion 15 was measured for three types. The result is shown in the graph of FIG.

On the other hand, as a comparative example, instead of the after sensor 1 of this embodiment, as shown in FIG.
3, the after sensor 21 in which the pressure sensitive portion 25 and the acrylic plate 27 are laminated was attached to the keyboard device K, and the resistance value was measured in the same manner as in the case of the after sensor 1 (referred to as Comparative Example 1). The result is shown in FIG.

The upper part of the horizontal axis of the graphs of FIGS. 4 (a) and 4 (b) shows the key pressing load of the single key of (A) and (C).
Further, the lower part of the horizontal axis shows the key pressing load in the case of three keys (B), and shows the total load applied to the three keys. In this way, the scale of the horizontal axis in the case of three keys is different from the resistance value in the case of single note performance and the resistance value of the chord performance of three keys (a load of twice the key pressing load of a single note is applied). This is to compare with.

Here, as is clear from FIG. 4 (a),
In the after sensor 1 of the example, the difference in resistance value between the white key (A) and the black key (C) was as small as 1 to 8Ω, which was very preferable. Further, the difference in resistance between the single tone (A) and the chord (B) was small, about 1 to 2Ω, which was very preferable.

On the other hand, as shown in FIG.
In the after sensor 21 of Comparative Example 1, the difference in resistance value between the case of the white key (A) and the case of the black key (C) was 4 to 11 Ω, which was large compared to the examples, which was not preferable. In addition, the difference in resistance between a single note (A) and a chord (B) is about 2
It was as large as ~ 6Ω, which was not preferable.

As described above, the after sensor 1 according to the present embodiment.
Then, by providing the load distribution member 13, it is possible to reduce the difference in the resistance value due to the difference in the contact area between the white key and the black key, and the difference in the resistance value between the single note and the chord. it can. Next, an experimental example 2 showing the effect of the buffer member 17 provided on the lower surface of the pressure sensitive portion 15 will be described.

In Experimental Example 2, in the keyboard device K provided with the after sensor 1 of this embodiment, the resistance value of the pressure sensitive portion 15 was measured when each white key having a different pitch was pressed by a single key.
On the other hand, as a comparative example, for an after sensor not provided with a double-sided cushion tape (a felt, a polycarbonate plate, a pressure-sensitive portion, and an acrylic plate are laminated in this order from the top), the resistance is the same as in the above-described example. The value was measured (referred to as Comparative Example 2). The result is shown in FIG. still,
The horizontal axis of the graph in FIG. 6 has letters (C, D ...
B) shows the note name (de, re ...) of each white key.

As is apparent from FIG. 6, in the after sensor 1 of this embodiment provided with the buffer member 17, the resistance value is about 1.
It is in the range of 7 to 26Ω, and the variation for each key is small,
I liked it very much. On the other hand, in the after sensor of Comparative Example 2 in which the buffer member 17 is not provided, the resistance value is 1
2 to 51 Ω, which was very large and was not preferable.

As described above, the after sensor 1 according to the present embodiment.
In the above, it was found that by providing the cushioning member 17 on the lower surface of the pressure sensitive portion 15, it is possible to reduce the variation in the resistance value for each key. As described above in detail, according to the after sensor 1 of this embodiment, by providing the load distribution member 15 made of a hard material (polycarbonate),
There is an effect that the difference in output resistance value due to the difference in contact area with each key and the difference in resistance value between a single note and a chord can be reduced.

Further, since the buffer member 17 is provided between the pressure sensitive portion 15 and the reinforcing member 19, it is possible to reduce the variation in the resistance value for each key due to the distortion of the shape of the load distribution member 13. effective. Further, the cushioning member 17 has an effect of preventing a short circuit between the pressure-sensitive portion 15 and the reinforcing member 19 and protecting the pressure-sensitive portion 15 from rust of the reinforcing member 17. Furthermore, since the double-sided cushion tape is used as the cushioning member 17, it is not necessary to apply an adhesive to the sticking surface, which facilitates manufacturing and reduces the overall thickness of the after sensor 1.

Further, in this embodiment, since stainless steel is used as the reinforcing member 19, it is possible to maintain the strength without increasing the thickness of the after sensor 1 as compared with an acrylic plate or the like. Further, since it is less likely to be plastically deformed as compared with a conventionally used zinc iron plate or the like, there is an effect that the pressure sensitive portion 15 is not adversely affected. Also, strong against rust,
This has the effect of not adversely affecting the pressure sensitive portion 15 and the like.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and may be implemented in various modes without departing from the scope of the present invention. Of course. For example, the pressure-sensitive section is not limited to the sensor as in the above-described embodiment, but various types can be used. For example, as a film sensor, a first film printed by laminating a conductive layer (electrode) and a pressure-sensitive layer and a second film printed only on the conductive layer are overlapped, and the electrode and the pressure-sensitive layer are interposed with a gap portion therebetween. It is also possible to use a sensor (for example, manufactured by Toshiba Silicon Co., Ltd., trade name: Siltouch) opposed to each other. A rubber sensor using conductive rubber (a conductive rubber sandwiched between two electrodes) can also be used. Furthermore, when light is passed through the inside of a rubber optical fiber (rubber optical fiber) and external force is applied to this rubber optical fiber, the total reflection condition collapses due to deformation, and the amount of light transmitted decreases. A sensor for detecting (for example, manufactured by Bridgestone,
The product name: Aness) can also be used.

Further, the cushioning member may be provided between the pressure sensitive portion and the load distribution member. Further, as the buffer member, urethane rubber or soft vinyl chloride resin may be adhered with an adhesive or the like. If a load distribution member that does not have distortion or protrusion in its shape and does not cause variations in the resistance value of each key can be used, these cushioning members do not necessarily have to be provided.

[0041]

As described above, in the after-touch sensor according to the first aspect of the present invention, the load distribution member made of a hard material is provided, so that the difference in the output value of the pressure sensitive portion due to the difference in the contact area with each key is provided. Can be made small, and a remarkable effect that a more uniform aftertouch effect can be obtained irrespective of the difference of keys such as a white key and a black key.

The aftertouch sensor according to the second aspect of the invention has an effect that the difference in resistance value between a single tone and a chord can be reduced, and a more uniform aftertouch effect can be obtained. Further, the after-touch sensor of claim 3 has an advantage that by providing the cushioning member, it is possible to reduce the variation in the output value for each key due to the distortion of the shape of the load distribution member.

Moreover, in the aftertouch sensor of the fourth aspect, since the reinforcing member made of stainless steel is provided in the lowermost layer, the strength can be maintained without increasing the overall thickness, and plastic deformation is caused. It's difficult and strong against rust,
It has the feature that it does not adversely affect the pressure sensitive part.

[Brief description of drawings]

1A and 1B show a keyboard device including an aftertouch sensor according to an embodiment of the present invention, FIG. 1A is a plan view thereof, FIG. 1B is a sectional view taken along line AA, and FIG. It is a figure.

2A and 2B are explanatory views of a pressure-sensitive portion of an after-touch sensor according to an embodiment, FIG. 2A is a perspective view showing a part of the pressure-sensitive portion in an exploded manner, and FIG. It is a graph which shows a resistance characteristic.

FIG. 3 is a partial perspective view showing the lower parts of the white key and the black key of the keyboard device of the embodiment.

FIG. 4 is a graph showing the results of Experimental Example 1.

5 is a cross-sectional view showing the structure of an aftertouch sensor of Comparative Example 1. FIG.

FIG. 6 is a graph showing the results of Experimental Example 2.

FIG. 7 is an explanatory diagram showing the operation of the present invention.

FIG. 8 is an explanatory diagram showing the operation of the present invention.

FIG. 9 is an explanatory diagram showing a conventional technique.

[Explanation of symbols]

 1 ... After-touch sensor 2 ... Keyboard 3 ... White key 5 ... Black key 13 ... Load distribution member 15 ... Pressure sensitive part 17 ... Buffer member 19 ... Reinforcement member

Claims (4)

[Claims] 1. An after-touch sensor for an electronic musical instrument, comprising a pressure-sensitive portion which is provided below a keyboard composed of a plurality of keys and whose output changes according to the pressing force applied by the keys being pressed. An aftertouch sensor for an electronic musical instrument, comprising a load distribution member formed of a hard material and configured to disperse a load applied by the key, on the upper surface side of the pressure sensitive portion. 2. The pressure sensitive portion has a pressure-resistance characteristic in which the resistance value decreases non-linearly and the rate of change thereof decreases as the pressing force applied by the key during the key pressing increases. The chord resistance value of the pressure-sensitive portion when a plurality of keys are pressed simultaneously is a pressure-sensitive portion that is a parallel sum of resistance values of the respective keys, and the pressure-sensitive portion is obtained by using the load distribution member. 2. An aftertouch sensor for an electronic musical instrument according to claim 1, wherein a region having a large change rate of a resistance value is used as a use region of the pressure-resistance characteristic of 1. 3. The after-sales of an electronic musical instrument according to claim 1, wherein a cushioning member that deforms according to a shape of the load distribution member is provided on an upper surface and / or a lower surface of the load distribution member. Touch sensor. 4. The bottom layer of the after-touch sensor,
The after-touch sensor for an electronic musical instrument according to claim 1, further comprising a reinforcing member made of stainless steel.