JP2020149385A - Passive stylus pen for electrostatic capacity type touch display and pen input system for touch display - Google Patents

Abstract

To provide, for example, a passive stylus pen for an electrostatic capacity type touch panel capable of realizing a line width expression in accordance with actual writing pressure without any limitation on the material and shape of a pen tip.SOLUTION: A passive stylus pen of the present invention is provided for an electrostatic capacity type touch display and includes: a first conductive contact part for making contact with a touch display; a second conductive contact part for making contact with a user; and an adjustment part which is connected to the first conductive contact part and the second conductive contact part and changes the amount of current flowing from the first conductive contact part to the second conductive contact part in accordance with stress added to the first conductive contact part.SELECTED DRAWING: Figure 2

Description

The present invention relates to a passive stylus pen for a capacitive touch display and a pen input system for a touch display.

In recent years, among touch displays, capacitive touch displays have become widespread. This capacitive touch display detects the position of the pen tip on the touch display screen by detecting, for example, the change in capacitance that occurs between the pen tip of the stylus pen and the touch display screen. Is. On the other hand, in recent years, it has become a standard for stylus pens used in capacitive touch displays to have a pen pressure detection function. This pen pressure detection function aims at writing expression like a brush by changing the thickness of the writing line displayed on the screen according to the writing pressure of the stylus pen when writing with the stylus pen. Is.

For example, a technique for controlling the line width written by using a stylus pen by a pseudo pen pressure detection function has been developed (see Patent Document 1).

However, the stylus pen having a pseudo pen pressure detection function assumes that there is a causal relationship between the strength of the force to grip the stylus pen and the pen pressure, and the strength of the force to grip the stylus pen is set to the writing thickness. It's just something to convert. Therefore, it may not be possible to express the line width according to the actual writing pressure.

The present invention has been made in view of the above circumstances, and provides a passive stylus pen for a capacitive touch panel and a pen input system for a touch panel that can realize a line width expression according to an actual writing pressure. The purpose is.

In order to solve the above-mentioned problems and achieve the object, the present invention comprises a first conductive contact portion for contacting the touch display, a second conductive contact portion for contacting the user, and the above-mentioned. The second conductive contact portion is connected to the first conductive contact portion and the second conductive contact portion, and the first conductive contact portion is connected to the second conductive contact portion according to the stress applied to the first conductive contact portion. It is a passive stylus pen for a capacitive touch display that includes an adjusting unit that changes the amount of current flowing through the contact unit.

According to the present invention, it is possible to realize a line width expression according to an actual writing pressure.

FIG. 1 is a diagram for explaining a pen input system 1 for a touch display according to the present embodiment. FIG. 2 is a diagram for explaining the configuration of the passive stylus pen 1, and is a cross-sectional view taken along the longitudinal direction of the passive stylus pen 1. FIG. 3 is a hardware configuration diagram of the touch display 2. FIG. 4 is a diagram showing an example of a circuit configuration of the display 280. FIG. 5 is a diagram for explaining the detection principle of a general touch display. FIG. 6 is a diagram for explaining the principle of detecting the position information of the touch display 2 by using the passive stylus pen 3 according to the present embodiment. FIG. 7 is a diagram for explaining the principle of detecting the position information of the touch display 2 using the passive stylus pen 3 according to the present embodiment. FIG. 8 is a diagram for explaining the principle of detecting the position information of the touch display 2 using the passive stylus pen 3 according to the present embodiment. FIG. 9A is a diagram showing an example of ideal stress-resistance value characteristics of the stylus pen 3. FIG. 9B is a diagram showing an example of the stress-resistance value characteristic showing the exponential phenomenon of the stylus pen 3 and the stress-resistance value characteristic of the stylus pen 3 according to the modified example. FIG. 10A is a diagram showing the configuration of the stylus pen 3 according to the modified example. FIG. 10B is a diagram for explaining the combined resistance of the stylus pen 3 according to the modified example.

Hereinafter, embodiments of the touch display pen input system and passive stylus pen according to the present invention will be described with reference to the accompanying drawings. The pen input system for a touch display is composed of a passive stylus pen and a capacitive touch display. In the following, the capacitive touch display will be referred to as an electronic blackboard for the sake of specific explanation. However, the present invention is not limited to this example, and the technical idea of the present invention can be applied even when the capacitive touch display is a smartphone, a tablet PC, or the like.

FIG. 1 is a diagram for explaining a pen input system 1 for a touch display according to the present embodiment. As shown in the figure, the pen input system 1 for a touch display is composed of a touch display 2 as an electronic blackboard and a passive stylus pen 3. The passive stylus pen 3 is gripped by the user 4. The user 4 can write on the touch display 2 by moving the pen tip of the passive stylus pen 3 in contact with the touch display 2.

FIG. 2 is a diagram for explaining the configuration of the passive stylus pen 3, and is a cross-sectional view taken along the longitudinal direction of the passive stylus pen 3. As shown in the figure, the passive stylus pen 3 includes a pen core portion 31 composed of a pen tip portion 34 (first conductive contact portion) and an insulating portion 35, a resistance type pressure sensor 32 (adjustment portion), and the like. It includes a non-conductive first housing portion 33 and a conductive second housing portion 37 (second conductive contact portion).

The pen tip portion 34 is made of a conductive material, one end of which functions as a contact portion that comes into contact with the touch display 2 during writing, and the other end is fixed to the insulating portion 35. The material and shape of the pen tip portion 34 are not limited, and a degree of freedom can be provided. For example, since the pen tip portion 34 does not necessarily have to have elasticity, it is possible to select a highly resistant material, design a writing comfort that does not kill movement, and design writing friction. Further, the tip portion of the pen tip portion 34 in contact with the touch display 2 may be made of a conductive material different from other portions as long as conductivity is ensured.

The resistance type pressure sensor 32 is a device that detects the value of the applied stress (pressure) and changes the resistance value R of the built-in pressure resistance element according to the value. One surface of the resistance type pressure sensor 32 is fixed to the bottom surface of the first housing portion 33. An insulating portion 35 is fixed to the other surface of the resistance type pressure sensor 32.

The second housing portion 37 is a gripping portion for gripping the passive stylus pen 3 when the user writes, and is integrally with the first housing portion 33 along the longitudinal direction of the passive stylus pen 3. Be connected. The second housing portion 37 may be electrically connected to the resistance type pressure sensor 32 and the user's hand, regardless of its shape, thickness, or position on the passive stylus pen 3. Further, the second housing portion 37 may be realized by electrically coating the non-conductive housing of the passive stylus pen 3.

The pen tip portion 34 and the resistance type pressure sensor 32 are electrically connected by wiring 38, and the resistance type pressure sensor 32 and the second housing portion 37 are electrically connected by wiring 39, respectively. When the passive stylus pen 3 is used, the pen tip portion 34 comes into contact with the touch display 2, and the second housing portion 37 is gripped by the hand of the user (human body). Therefore, when the pen tip portion 34 comes into contact with the touch display 2, the user (hand) 4 to be grounded and the surface of the touch display 2 are electrically connected via the pen tip portion 34 and the resistance type pressure sensor 32. Will be.

Further, when the user writes on the touch display 2 using the passive stylus pen 3, one end of the pen tip 34 is in contact with the touch display 2, and the insulating portion 35 fixed to the other end of the pen tip 34. Is in contact with the resistance type pressure sensor 32. When one end of the pen tip 34 moves while contacting the touch display 2, the stress applied to one end of the pen tip 34 is a resistance pressure through the insulating portion 35 fixed to the other end of the pen tip 34. It will be transmitted to the sensor 32 at any time. The resistance type pressure sensor 32 converts the stress value transmitted at any time into the resistance R1. That is, the resistance R1 of the resistance type pressure sensor 32 is adjusted according to the stress transmitted at any time.

The lower the impedance of the pen tip portion 34, the resistance R1 of the resistance type pressure sensor 32, and the second housing portion 37, the larger the detection value of the touch display 2. Therefore, if the pen input system 1 for a touch display cannot be designed with high sensitivity, a highly conductive material may be selected for the pen tip portion 34, the resistor R1 of the resistance type pressure sensor 32, and the second housing portion 37. It is desirable to adjust the correlation between the stress and the resistance value R1 by selecting the resistance type pressure sensor 32 and designing the circuit around the resistance R1. In addition to the above factors, the detected values in the pen input system 1 for touch display include the contact area between the pen tip 34 and the touch display 2 and the glass thickness of the panel (distance between the pen tip and the electrode on the touch display 2 side). It also depends on such things.

FIG. 3 is a hardware configuration diagram of the touch display 2. As shown in FIG. 3, the touch display 2 includes a CPU (Central Processing Unit) 201, a ROM (Read Only Memory) 202, a RAM (Random Access Memory) 203, an SSD (Solid State Drive) 204, and a network I / It includes an F205 and an external device connection I / F (Interface) 206.

Of these, the CPU 201 controls the operation of the entire touch display 2. The ROM 202 stores a program used to drive the CPU 201 such as the CPU 201 and the IPL (Initial Program Loader). The RAM 203 is used as a work area of the CPU 201. The SSD 204 stores various data such as a program for an electronic blackboard. The network controller 205 controls communication with the communication network 100. The external device connection I / F 206 is an interface for connecting various external devices. The external device in this case is, for example, a USB (Universal Serial Bus) memory 230 and an external device (microphone 240, speaker 250, camera 260).

Further, the touch display 2 includes a capture device 211, a GPU 212, a display controller 213, a contact sensor 214, a sensor controller 215, a short-range communication circuit 219, an antenna 219a of the short-range communication circuit 219, a power switch 222, and selection switches 223. I have.

Of these, the capture device 211 causes the display of the external PC (Personal Computer) 270 to display the video information as a still image or a moving image. The GPU (Graphics Processing Unit) 212 is a semiconductor chip that specializes in graphics.

The display controller 213 controls and manages the screen display in order to output the output image from the GPU 212 to the display 280 or the like. For example, the display controller 213 controls the width of the line to be displayed on the display 280 by writing with the passive stylus pen 3 according to the amount of change in the current waveform detected by the contact sensor 214. The control may be realized by dedicated application software.

FIG. 4 is a diagram showing an example of a circuit configuration of the display 280. As shown in the figure, the display 280 includes a transmission electrode Txi (i is a natural number of 1 ≦ i ≦ N), a reception electrode Rxj (a natural number of j1 ≦ j ≦ N), and a pulse generator (not shown in FIG. 4). ), The amplifier 303 (not shown in FIG. 4). The transmitting electrode Txi and the receiving electrode Rxj are orthogonal to each other. Assuming that the direction along the transmitting electrode Txi is the X-axis and the direction along the receiving electrode Rxj is the Y-axis, a large number of parallel sensor lines are formed in each of them to form a grid-like electrode pattern. When a drive pulse is transmitted from the pulse generator 302 to the transmission electrode Txi, an electric field is generated between the transmission electrode Txi and the Rxj electrode, and a plurality of capacitors each having a capacitance Cp and arranged in a grid pattern are formed.

The contact sensor 214 detects that the passive stylus pen 3 or the user's hand has come into contact with the display 280. That is, as shown in FIG. 4, the contact sensor 214 is a capacitor in which the capacitance Cp is changed (hatched portion in FIG. 4) among a plurality of capacitors arranged in a grid pattern on the display 280 as shown in FIG. ) Is detected to identify the contact position. Further, the contact sensor 214 has a function of detecting a change amount of each current waveform 42 detected from a plurality of capacitors.

Returning to FIG. 3, the sensor controller 215 controls the processing of the contact sensor 214. The short-range communication circuit 219 is a communication circuit such as NFC (Near Field Communication) or Bluetooth (registered trademark). The power switch 222 is a switch for switching ON / OFF of the power of the touch display 2. The selection switches 223 are, for example, a group of switches for adjusting the brightness and hue of the display of the display 280.

Further, the touch display 2 includes a bus line 210. The bus line 210 is an address bus, a data bus, or the like for electrically connecting each component such as the CPU 201 shown in FIG.

FIG. 5 is a diagram for explaining the detection principle of the general capacitive touch display 2. As shown in the figure, when the grounded user's finger (human body finger) F approaches the surface of the capacitive touch display 2, a weak current is generated between the surface of the touch display 2 and the finger. A capacitor 14 having a capacitance of Cf is formed between the sensor electrode 13 including the transmitting electrode Txi electrode and the receiving electrode Rxj and the fingertip. When the capacitor 14 having the capacitance Cf is formed, among the plurality of capacitors shown in FIG. 4, the capacitor corresponding to the position of the finger on the surface of the touch display 2 (the position where the capacitor 14 having the capacitance Cf is formed) is formed. The capacitance Cp of the capacitor corresponding to (the shaded portion in FIG. 4) increases (that is, the electric field between the transmitting electrode Txi electrode and the receiving electrode Rxj decreases). As a result, the value of the current waveform detected from the receiving electrode decreases, and the approach of the human body is detected based on this decrease amount. Further, by outputting a drive signal to the X-axis sensor line (transmission electrode Txi) and reading each signal (each current waveform) from the Y-axis sensor line (reception electrode Rxj), detection on the entire surface of the two touch display screens is performed. Since the two-dimensional distribution of the values is calculated, it is possible to calculate the touch position.

When the capacitance method is classified in more detail, it is classified into a surface type and a projection type according to the difference in the detection mechanism. Further, the projection type is classified into a mutual capacitance type and a self-capacity type. In this embodiment, in order to make the explanation concrete, the mutual capacitance type generally adopted in smartphones and tablets is taken as an example, but the basic principle of contact position detection is based on any type of touch display. As mentioned above.

6, 7, and 8 are diagrams for explaining the principle of detecting the position information of the touch display 2 by using the passive stylus pen 3 according to the present embodiment. As shown in FIG. 6, when the pen tip portion 34 of the passive stylus pen 3 approaches the surface of the capacitive touch display 2, a weak current is generated between the surface of the touch display 2 and the pen tip portion 34. Then, a capacitor 14 having a capacitance Cf is formed between the sensor electrode 13 including the transmitting electrode Txi electrode and the receiving electrode Rxj and the pen tip portion 34.

On the other hand, as shown in FIG. 7, the passive stylus pen 3 between the user 4's hand and the touch display 28 serves as a conductive path. The impedance in this path changes in conjunction with the change in the resistance of the resistance type pressure sensor 32 according to the writing pressure. That is, this conductive path includes the pressure resistance element R of the resistance type pressure sensor 32 that changes its resistance in conjunction with the change in writing pressure. Therefore, in this conductive path, if the piezoresistive element R becomes smaller (the impedance becomes smaller) as the writing pressure increases, more electric charge moves to the human body (user) side, so that it is formed at the contact position. The capacitance Cf of the capacitor increases.

As shown in FIGS. 7 and 8, when the drive pulse 41 is transmitted from the pulse generator 302 to the transmission electrode Txi, an electric field is generated between the pulse generator 302 and the Rxj electrode, and each has a capacitance Cp and is arranged in a grid pattern. A plurality of the capacitors are formed. When the capacitance Cf increases, among the plurality of capacitors shown in FIG. 8, the capacitor corresponding to the contact position of the passive stylus pen 3 (the capacitor corresponding to the position where the capacitor 14 of the capacitance Cf is formed). In No. 4, the capacitance Cp of the shaded portion) increases (that is, the electric field between the transmitting electrode Txi electrode and the receiving electrode Rxj decreases).

The decrease in the electric field between the transmitting electrode Txi electrode and the receiving electrode Rxj is linked to the change in the capacitance Cf (or the impedance of the conductive path including the resistance pressure sensor 32) between the sensor electrode 13 and the pen tip 34. Will occur. As a result, as shown in FIG. 8, the value of the current waveform 42 detected from the receiving electrode Rxj changes by the amount of decrease 45 according to the writing pressure. If the writing line width is continuously changed and displayed according to the amount of change in the current waveform, a writing expression in which the writing line width is continuously changed according to the writing pressure becomes possible. Table 1 shows an example of the characteristic that the resistance value of the resistance type pressure sensor 32 decreases and the capacitance Cf increases between the sensor electrode 13 and the pen tip 34 as the writing stress increases.

As for the position information, as shown in FIG. 8, the position where the waveform has changed may be specified from the two-dimensional distribution of the current waveform. Further, the pen pressure information may be calculated based on the amount of change in the current waveform in which the change is specified, and the line width displayed on the touch display 2 may be controlled. In this way, using the same configuration as a general touch sensor, it is possible to add not only touch position information but also continuous pen pressure information to the detected current waveform. The display controller 213 draws a line at a touch position specified based on the acquired position information, and further changes the displayed line width according to the pen pressure information. As a result, the input display system has a line width drawing function corresponding to the actual writing pressure.

(effect)
As described above, according to the pen input system for a touch display and the passive stylus pen 3 according to the embodiment of the present invention, the pen tip portion 34 (first conductive contact portion) for contacting the touch display and the passive stylus pen 3 It is connected to the second housing portion 37 (second conductive contact portion) for contacting with the user, and the pen tip portion 34 to the second housing portion 37 responds to the stress applied to the pen tip portion 34. The amount of current flowing to is changed by the resistance type pressure sensor 32.

The stronger the stress (writing pressure) on the pen tip portion 34 of the stylus pen 3, the smaller the resistance value R of the resistance type pressure sensor 32, and the smaller the impedance between the user's hand and the touch display 2. Then, since more electric charges move to the human body (user) side, the capacitance Cf of the capacitor formed at the contact position between the touch display 2 and the stylus pen 3 increases. As described above, as the writing stress increases, the resistance value R of the pressure resistance element of the resistance type pressure sensor 3 decreases, and the electric charge of the capacitor generated between the human body and the touch display 2 can be changed. Further, the capacitance Cp of the capacitor corresponding to the contact position of the passive stylus pen 3 can be increased in conjunction with the increase of the capacitance Cf (that is, the electric field between the transmitting electrode Txi electrode and the receiving electrode Rxj is reduced). Can be made to). Therefore, the value of the current waveform 42 detected from the receiving electrode Rxj can be changed by a reduction amount of 45 according to the writing pressure, and the writing line width is continuously changed and displayed according to the change amount of the current waveform. Then, it becomes possible to perform a written expression in which the line width is continuously changed according to the writing pressure.

As a result, according to the passive stylus pen, which is a pen input system for a touch display according to the embodiment of the present invention, it is possible to realize a line width expression according to an actual writing pressure.

In the conventional passive stylus pen, since there is no causal relationship between the force of gripping the stylus pen and the writing pressure, it is not possible to perform writing expression with a line width depending on a parameter derived from the actual writing pressure. Therefore, when the force of gripping the stylus pen changes while writing with the same writing pressure, there is a problem that the writing is expressed with a line width that does not correspond to the actual writing pressure. It is clear that such a problem does not occur with the passive stylus pen 3 according to the embodiment of the present invention.

Although the embodiment according to the present invention has been described above, the present invention is not limited to the above-described embodiment as it is, and at the implementation stage, the components can be modified and embodied without departing from the gist thereof. In addition, various inventions can be formed by an appropriate combination of the plurality of components disclosed in the above-described embodiment. For example, some components may be removed from all the components shown in the embodiments described above.

Further, the pen tip portion 34 may be made of a conductive material, and the material, shape, and the like thereof can be freely selected. Therefore, the pen tip portion 34 of a desired material and shape is selected for fine writing movements in the plane direction and the vertical direction with respect to the panel, writing ability by increasing or decreasing the area of the pen tip, durability of the pen tip, writing comfort due to writing friction, and the like. By doing so, you can customize it freely.

FIG. 9A is a diagram showing an example of ideal stress-resistance value characteristics of the stylus pen 3. In the configuration of the stylus pen 3 shown in FIG. 2, it is desirable to select an element having the ideal stress-resistance value characteristic A as shown in FIG. 9A. However, the element exhibiting the ideal stress-resistance value characteristic A may not satisfy the design requirements (element size, etc.) of the stylus pen 3. In such a case, it is possible to adjust the stress-resistance value characteristic of the stylus pen 3 by designing the resistance value of the circuit.

FIG. 9B is a diagram showing an example of the stress-resistance value characteristic B showing the exponential phenomenon of the stylus pen 3 and the stress-resistance value characteristic of the stylus pen 3 according to the modified example. When the stress-resistance value characteristic B shown in FIG. 9B shows an extremely exponential decrease in the writing stress range, the stylus pen 3 is touched because the internal impedance of the stylus pen 3 is too large when writing with a weak writing pressure. It may not be detected.

Therefore, in the stylus pen 3 according to the first modification, as shown in FIG. 10A, the fixed resistor 51 having the resistance value Rs is connected in parallel to the resistance type pressure sensor 32 having the resistance value Rp. With such a circuit configuration, as shown in FIG. 10B, a combined resistor 53 having a resistance value R2 is formed in the conductive path inside the stylus pen 3. Assuming that the initial resistance value (when the stress is zero) of the resistance type pressure sensor 32 is infinite, the resistance value R2 of the combined resistance is substantially equal to the resistance value Rs of the fixed resistor 51, and the stress of the stylus pen 3- The resistance value characteristic can be modified to have a linear behavior such as the straight line C in FIG. 10 (b). Therefore, the resistance value inside the stylus pen 3 can be reduced from infinity to a predetermined value even when the stress is extremely weak, and the contact position of the stylus pen 3 with the touch display 3 and the fluctuation of the current waveform can be reduced. Can be detected.

Further, in the above embodiment, the case where the resistance type pressure sensor 32 is used as the adjusting unit for adjusting the amount of current flowing from the first conductive contact portion to the second conductive contact portion has been exemplified. However, the technical idea of the present invention is not limited to this example. For example, instead of the resistance type pressure sensor 32, an element having a piezoelectric effect may be used instead of the resistance type pressure sensor 32.

1 Pen input system for touch display 2 Touch display 3 Passive stylus pen 14 Contact sensor 31 Pen core part 32 Resistance type pressure sensor 33 First housing part 34 Pen tip part 35 Insulation part 37 Second housing part 38 Wiring 39 Wiring 41 Pulse 42 Current waveform 45 Decrease (change)
201 CPU
202 ROM
203 RAM
204 SSD
205 Network I / F
206 External device connection I / F
211 capture device 212 GPU
213 Display controller 214 Contact sensor 215 Sensor controller 222 Power switch 223 Select switch 240 Microphone 250 Speaker 260 Camera 270 PC
280 Display 302 Pulse Generator 303 Amplifier

Japanese Patent No. 5944289

Claims (7)

The first conductive contact part for contacting the touch display,
A second conductive contact for contact with the user,
The second conductive contact portion is connected to the first conductive contact portion and the second conductive contact portion, and the first conductive contact portion is connected to the second conductive contact portion according to the stress applied to the first conductive contact portion. An adjustment unit that changes the amount of current flowing to the sex contact part,
Passive stylus pen for capacitive touch displays equipped with. The passive stylus pen according to claim 1, wherein the adjusting portion is a piezoresistive element whose resistance value changes according to stress. The passive stylus pen according to claim 1, wherein the adjusting portion is a piezoelectric element whose voltage changes according to stress. The passive stylus pen according to any one of claims 1 to 3, further comprising a resistor connected in parallel with the adjusting unit. The passive stylus pen according to any one of claims 1 to 4, wherein the passive stylus pen is any one of a surface type, a self-capacity type of projection method, and a mutual capacitance type of projection method. The adjusting portion is linked to a change in the capacitance of the capacitor formed between the first conductive contact portion and the touch display, and the first conductive portion of the plurality of capacitors of the touch display is linked. The passive stylus pen according to any one of claims 1 to 5, wherein the charge of the capacitor corresponding to the position where the contact portion contacts the touch display is changed. A pen input system for a touch display equipped with a passive stylus pen and a capacitive touch display.
The passive stylus pen
A first conductive contact portion for contacting the touch display,
A second conductive contact for contact with the user,
The second conductive contact portion is connected to the first conductive contact portion and the second conductive contact portion, and the first conductive contact portion is connected to the second conductive contact portion according to the pressure applied to the first conductive contact portion. An adjustment unit that changes the amount of current flowing to the sex contact part,
Have,
The touch display is
It has a control unit that controls a line width to be displayed based on a current waveform for position detection that changes based on the amount of current.
Pen input system for touch display.

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