JP5151808B2 - Information input device - Google Patents

Description

  The present invention relates to an information input device using capacitance.

  In a touch panel using the electrostatic capacity method, a hand or pen is brought into contact with the screen to form an electrostatic capacity (capacitor), and a contact position is detected by detecting a change in a weak current flowing through the capacitor. Is detected. And in this touch panel using the electrostatic capacity method, hand input by a fingertip or handwriting input using a pen (pen input) is basically employed. However, when a character or the like is input by hand using a pen. The hand is easy to touch the touch panel. For this reason, unless the contact with the pen and the contact with the hand can be discriminated, characters or the like cannot be accurately input with the pen. Therefore, in order to discriminate between contact with a pen and contact with a hand, it is necessary to input a signal for discriminating which input is to be used at the time of manual input or pen input. Examples of such a technique for distinguishing between pen input and manual input include the following first and second conventional techniques.

  In the first prior art, a specific electric signal is generated from an oscillator provided inside the pen, and pen input and manual input are distinguished depending on whether or not the electric signal is detected (for example, Patent Document 1). . In the second prior art, the signal generator incorporated in the pen is capable of switching the frequency of the signal by the operator, and it is determined whether or not the input is a pen by switching the frequency. (For example, Patent Document 2). That is, in both the first and second prior arts, it is determined whether or not the input is a pen by changing the frequency of the signal.

JP-A-7-129321 JP-A-7-104908

  However, in these techniques, it is necessary to provide an oscillator, a signal generator, and a power source for driving them inside the pen. For this reason, the configuration of the pen becomes complicated, and the operability of the pen is hindered by a load due to an increase in the weight of the pen.

  The present invention has been made in view of the above problems, and by appropriately detecting the contact position of the pen while ensuring comfortable operability, it is possible to provide a capacitance that enables accurate input using the pen. An object is to provide a used information input device.

In order to solve the above-described problem, the invention described in claim 1 includes a stylus pen for inputting a character or a diagram, a panel portion having an insulating film and a conductive film, and a plurality of reference positions of the conductive film. On the other hand, a signal applying unit that sequentially applies first and second frequency signals having a frequency lower than a predetermined frequency and a third frequency signal having a frequency higher than the predetermined frequency, and the stylus to the insulating film A current detection unit for detecting a current flowing through each of the reference positions due to capacitive coupling generated in response to a touch of a pen and an operator's hand; and the first and second with respect to the plurality of reference positions When the third frequency signal is applied to the plurality of reference positions from the first and second currents respectively detected by the current detector when the frequency signal is applied, the current detection is performed. A third current generated in response to the contact of the operator's hand detected by the unit is virtually calculated, and the current detection unit is provided when the third frequency signal is applied to the plurality of reference positions. Position detection for detecting the contact position of the stylus pen with respect to the panel unit based on the difference between the fourth current and the third current generated in response to simultaneous contact of the stylus pen and the operator's hand detected by comprising a part, the said conductive film is information input apparatus characterized that you have been arranged as a single electrode to cover the entire surface of all pixels of the panel portion.

  The invention according to claim 2 is the information input device according to claim 1, wherein the stylus pen is brought into contact with the insulating film, a tip portion for grounding, and a grounding terminal for grounding. The first and second resistors having different resistance values, and the tip portion, the first resistor, and the grounding terminal are electrically connected in series between the tip portion and the grounding terminal. 1 state of connection, and a state setting part that selectively sets the second end state, the second resistor and the grounding terminal are electrically connected in series, and the state The image processing apparatus further includes a color changing unit that changes a color of a character and / or a diagram input by the stylus pen based on the difference that is switched according to a state setting by the setting unit.

  The invention according to claim 3 is the information input device according to claim 1, wherein the stylus pen is in contact with the insulating film, a tip portion for grounding, and a grounding terminal for grounding. The first and second resistors having different resistance values, and the tip portion, the first resistor, and the grounding terminal are electrically connected in series between the tip portion and the grounding terminal. 1 state of connection, and a state setting part that selectively sets the second end state, the second resistor and the grounding terminal are electrically connected in series, and the state A state in which a character and / or diagram is input by the stylus pen and a state in which the character and / or diagram is erased by the stylus pen based on the difference that is switched according to the state setting by the setting unit switching And further comprising a.

  According to the first aspect of the present invention, in the pen input in which the hand and the stylus pen are simultaneously in contact with the panel, the signal is detected by sequentially applying signals of two types of high and low frequencies to the conductive film of the panel unit. The contact position of the stylus pen is appropriately detected based on the difference in current. For this reason, accurate input using a stylus pen is possible. Also, with such a configuration, the stylus pen configuration is not complicated, and the load due to the weight of the stylus pen is not increased, so that comfortable character input that does not hinder operability is possible.

  According to the second aspect of the present invention, it is possible to input a character or a diagram of a plurality of colors with a single stylus pen.

  According to the third aspect of the present invention, it is possible to input and erase characters and diagrams with a single stylus pen.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.

[First embodiment]
<Information input device>
FIG. 1 is a block diagram illustrating a functional configuration of an information input device 50 according to the first embodiment of the invention.

  As shown in FIG. 1, the information input device 50 includes a main body unit 1 and a stylus pen 20, and the main body unit 1 includes a panel unit 2, an oscillator 3, a detection circuit 4, a control unit 5, an operation unit 6, and a memory. Part 7 is provided.

  The information input device 50 is configured such that the tip of the stylus pen 20 is brought into contact with the panel unit 2 adopting the electrostatic capacitance method in a form such as a user holding the stylus pen 20 in his / her hand. Characters and line diagrams are input at the contact position.

  The panel unit 2 is a part for displaying a two-dimensional image, and constitutes a screen having a rectangular outline. FIG. 2 is a diagram schematically showing a cross section of the structure of the panel unit 2 and the stylus pen 20. As shown in FIG. 2, the panel unit 2 is configured by laminating a substrate 33, a transparent conductive film 32, and an insulating layer 31 on a liquid crystal display unit (not shown). Specifically, a transparent conductive film (electrode) 32 made of a conductive material is formed on a base material 33 made of a transparent film, glass or the like, and further an insulating material is made on the transparent conductive film 32. An insulating layer 31 is stacked.

  The transparent conductive film 32 is made of a material that is conductive and transparent, such as indium tin oxide (ITO), and is disposed as a single electrode so as to cover the entire surface of all the pixels of the panel unit 2. ing. The transparent conductive film 32 is used to detect a contact position of the hand or the stylus pen 20, that is, an information input position.

  FIG. 3 is a plan view of the transparent conductive film 32 as viewed from above. As shown in FIG. 3, the transparent conductive film 32 is applied with potentials from four directions at each end (+ x, −x, + y, −y) forming a rectangular extension. Specifically, the four end portions are substantially orthogonal to the adjacent end portions, and serve as a two-dimensional (XY direction) reference position for detecting a position where the stylus pen 20 and the hand are in contact with each other. Moreover, the insulating layer 31 is comprised by AR coating (Anti-Reflection Coat) which has an antireflection function, for example.

  As shown in FIG. 2, the stylus pen 20 is held by the operator's hand, and the front end of the stylus pen 20 is brought into contact with the panel unit 2 to input characters and a diagram to the panel unit 2. Is. The stylus pen 20 includes a pen body portion 21, a pen tip portion 22, a conductive portion 23 made of metal, a connection terminal 24 that is a ground terminal, and a connection cable 25. The pen tip portion 22 and the conductive portion 23 are electrically connected by a predetermined conductive member. The pen tip 22 is for making contact with the insulating layer 31 when inputting characters and diagrams, and is made of a conductive material such as aluminum, for example. The diameter of the pen tip 22 is, for example, The one with a diameter of about 3 mm is used. The conductive portion 23 is provided with a connection terminal 24. The connection terminal 24 is further provided with a connection cable 25. The stylus pen 20 is connected to the main body of the panel portion 2 by the connection cable 25 for the purpose of grounding.

  Returning to FIG. 1, the description will be continued. The oscillator 3 applies a low-frequency signal and a high-frequency signal to the transparent conductive film 32 of the panel unit 2 in time sequence. Here, the low frequency range is, for example, 50 to 120 KHz, and the high frequency range is, for example, 1 MHz to 100 MHz.

  The detection circuit 4 detects the current flowing through each reference position of the transparent conductive film 32 due to the capacitive coupling generated in response to the contact of the stylus pen 20 and the operator's hand with the insulating layer 31.

  The control unit 5 comprehensively controls the operation of the information input device 50. For example, the control unit 5 includes a CPU, and executes various programs and functions by executing a program stored in the storage unit 7 described later. Realize. For example, the control unit 5 includes a position detection unit 11, and the position detection unit 11 detects a contact position of the stylus pen 20 with respect to the panel unit 2 based on a signal corresponding to a detection result by the detection circuit 4.

  The operation unit 6 includes a keyboard, a mouse, and the like. When the user appropriately operates the operation unit 6, the operation unit 6 transmits various command signals corresponding to the operation to the control unit 5.

  The storage unit 7 is configured by a storage device such as a semiconductor memory or a hard disk, and stores a program executed by the control unit 5 and information necessary for executing the program.

<Principle of information input>
FIG. 4 is a diagram illustrating an information input mode in the panel unit 2.

  As shown in FIG. 4, in the information input device 50, by touching the panel unit 2 with the finger Fr, the dedicated stylus pen 20, or the like from the insulating layer 31 side, characters, figures, etc. are directly applied to the display image. Can be written. Here, an example in which writing is performed with the finger Fr will be described.

  5 and 6 are diagrams for explaining a method of detecting a position touched with the finger Fr, that is, an input coordinate of information. Here, a so-called capacitance method is employed.

  FIG. 5 shows a one-dimensional detection method of information input coordinates.

  An AC power source E1 is electrically connected to one end of the transparent conductive film 32 via a predetermined resistor Rr1, and an AC power source E2 is electrically connected to the other end of the transparent conductive film 32 via a predetermined resistor Rr2. It is connected. Each AC power source E1, E2 is grounded on the opposite side to the transparent conductive film 32.

  The transparent conductive film 32 receives AC voltage (potential e) having the same phase and the same frequency from both ends. At this time, if there is no touch such as the finger Fr, the potential applied from both ends is always the same, so that no current is generated in the transparent conductive film 32. However, if both ends of the surface of the screen are points A and B, so-called capacitive coupling occurs at point C when the finger Fr touches a certain position (point C).

  Here, the electrical resistance between both ends of the transparent conductive film 32 is R, the resistance from the end on the point A side of the transparent conductive film 32 to the point immediately below the point C is R1, and the end of the transparent conductive film 32 on the point B side is Assuming that the resistance immediately below the point C is R2, the following equation (1) is established.

  R = R1 + R2 (1)

  Then, due to capacitive coupling at point C, a current corresponding to the alternating voltage (potential e) applied to the transparent conductive film 32 is generated at the finger Fr. The same current as this current is also generated on the transparent conductive film 32 side. Here, since the potentials at both ends are the same at e, the amount of change in voltage from both ends of the transparent conductive film 32 to immediately below the point C has the same value. At this time, if the voltage change caused by capacitive coupling related to the finger Fr is e1, the current flowing through the resistor Rr1 is i1, and the current flowing through the resistor Rr2 is i2, the following equations (2) and (3) are established.

  e1 = i1 * R1 = i2 * R2 (2)

  R1 / R2 = i2 / i1 (3)

  Therefore, assuming that the resistance per unit length of the transparent conductive film 32 is constant, the coordinates of the position touched by the finger Fr can be detected by measuring the currents i1 and i2 flowing through the resistors Rr1 and Rr2. .

  FIG. 6 shows a method for detecting input coordinates of information on the screen of the panel unit 2. As shown in FIG. 6, AC power supplies E <b> 1 to E <b> 4 are electrically connected to the four ends of the transparent conductive film 32 via predetermined resistors, respectively. The AC power supplies E <b> 1 to E <b> 4 are respectively connected to the transparent conductive film 32. The opposite side is grounded. At this time, when the surface of the panel unit 2 is touched with the finger Fr, by measuring the current flowing through the resistors respectively connected to the four sides of the transparent conductive film 32, the finger Fr among the surface of the panel unit 2 is measured. The coordinates of the touched position are detected. Therefore, the oscillator 3 and the detection circuit 4 apply the AC voltage and measure the current to the transparent conductive film 32 described above, and the information input position is detected.

<Detection of stylus pen contact position>
(1) Principle for distinguishing between stylus pen contact and hand contact When a character or the like is input by hand using the stylus pen 20, if the stylus pen 20 contact and the hand contact cannot be distinguished, the stylus pen 20 It is not possible to input characters correctly. First, the principle for discriminating contact by hand and contact by stylus pen 20 will be described.

  FIG. 7 is a diagram showing an example of a panel unit and an equivalent circuit of a human body for explaining the principle of discriminating contact by hand and contact by stylus pen 20. In the equivalent circuit of the panel unit 2 in FIG. 7, the voltage is constant, and a low frequency signal of 100 KHz and a high frequency signal of 2 MHz are sequentially applied from the oscillator 3 to the transparent conductive film 32 of the panel unit 2. It will be described as being done.

  In the equivalent circuit of the panel unit 2, for example, two 200Ω resistors R3 are configured in parallel. The equivalent circuit of the human body is composed of a resistance R4 of 100000Ω and a capacitor of 100 pF, and the impedance including the capacitance and resistance of the capacitor when the hand is in contact with the panel unit 2 is Z. The capacitance Ct in the capacitive coupling when the human body comes into contact with the panel portion depends on the contact area with the insulating layer 31. For example, when a part of the hand comes into contact with the panel portion 2, a capacitive coupling of 400 pF occurs. When the stylus pen 20 comes into contact with the panel unit 2, a capacitive coupling of 2 pF occurs.

(A) When the frequency of the signal applied to the transparent conductive film 32 is 100 KHz and the voltage is 1 V:
A current i5 that flows when the stylus pen 20 contacts the panel unit 2 is expressed by the following equation (4). Here, V is the voltage value of the signal applied from the oscillator 3, R is the resistance value of the circuit, f is the frequency of the applied signal, and C is the capacitance of the capacitor of the circuit.

i5 = V × 1 / √ { (R + Z) 2 + 1 / (2π · f · C) 2} = 1 / √ {100203 2 + 1 / (2 × 3.14 × 100000 × 2 × 10- 12) 2} = 1.3 μA (4)

  The current i6 that flows when the hand holding the stylus pen 20 and the stylus pen 20 contacts the panel unit 2 is expressed by the following equation (5).

i6 = V × 1 / √ { (R + Z) 2 + 1 / (2π · f · C) 2} = 1 / √ {100203 2 + 1 / (2 × 3.14 × 100000 × 400 × 10- 12) 2} = 9.8 μA (5)

(B) When the frequency of the signal applied to the transparent conductive film 32 is 2 MHz and the voltage is 1 V:
The current i7 that flows when the stylus pen 20 comes into contact is expressed by the following equation (6).

i7 = V × 1 / √ {(R + Z) ² + 1 / (2π · f · C) ² } = 1 / √ {100203 ² + 1 / (2 × 3.14 × 100000 × 2 × 10 ⁻¹² ) ² } = 9.3 μA (6)

  The current i8 that flows when the hand holding the stylus pen 20 and the stylus pen 20 contacts the panel unit 2 is expressed by the following equation (7).

i8 = V × 1 / √ {(R + Z) ² + 1 / (2π · f · C) ² } = 1 / √ {100203 ² + 1 / (2 × 3.14 × 100000 × 400 × 10 ⁻¹² ) ² } = 10.0 μA (7)

  The equivalent circuit shown in FIG. 7 forms a CR high-pass filter. When the stylus pen 20 comes into contact with the panel unit 2, the current in the low frequency region is cut. A frequency (low frequency cutoff frequency) f1 of a signal indicating a threshold at which the current in the low frequency region is cut is expressed by the following equation (8).

f1 = 1 / (2π · f · C × (R + Z)) = 1 / (2 × 3.14 × 2 × 10 ⁻¹² × 100203) = 795 KHz (8)

  Moreover, when a hand contacts the panel part 2, the low-pass cutoff frequency f2 is shown by the following Formula (9).

f2 = 1 / (2π · f · C × (R + Z)) = 1 / (2 × 3.14 × 400 × 10 ⁻¹² × 100203) = 4 KHz (9)

  Due to the presence of the low-frequency cut-off frequencies f1 and f2, when a low-frequency signal of 100 KHz is applied to the transparent conductive film 32, contact of the stylus pen 20 is not detected and a high-frequency signal of 2 MHz is transmitted to the transparent conductive film 32. When it is applied to, the contact of both the stylus pen 20 and the hand holding the stylus pen 20 is detected. Therefore, from the current detected by the detection circuit 4 when a low frequency signal is applied to the plurality of reference positions of the transparent conductive film 32 of the panel unit 2, the high frequency is supplied from the oscillator 3 to the plurality of reference positions. A current generated according to the contact of the operator's hand detected by the detection circuit 4 when the signal is applied is virtually calculated, and a high frequency signal is applied from the oscillator 3 to a plurality of reference positions. Current generated in response to simultaneous contact of the stylus pen 20 and the operator's hand detected by the detection circuit 4, and the operator's hand when the virtually calculated high frequency signal is applied. The contact position of the stylus pen 20 with respect to the panel unit 2 is detected based on the difference from the current generated in response to the contact.

(2) Specific Detection Processing of Contact Position of Stylus Pen Next, specific processing in which the position detection unit 11 of the control unit 5 detects the contact position of the stylus pen 20 with respect to the panel unit 2 will be described.

  FIG. 8 is a diagram showing an equivalent circuit of the panel unit 2 and the human body of the present embodiment. Here, it is assumed that the voltage is constant, and low frequency signals of 100 KHz and 120 KHz and high frequency signals of 2 MHz are applied from the oscillator 3 to the transparent conductive film 32 of the panel unit 2. In the equivalent circuit of the panel unit 2, two RΩ resistors R <b> 5 are configured in parallel. When the hand touches the panel unit 2, Cte [pF] capacitive coupling occurs, and the stylus pen 20 contacts the panel unit 2. When this occurs, capacitive coupling of Cpen [pF] occurs. The equivalent circuit of the human body is composed of a resistor and a capacitor, and the impedance including the capacitance and resistance of the capacitor when the hand is in contact with the panel unit 2 is Z as in FIG. For example, Cpen = 2 [pF] for the contact of the stylus pen 20, and Cte = 400 [pF] for the contact of the hand at the time of input using the stylus pen 20.

  In the equivalent circuit of FIG. 8, the detection current it that flows when the hand holding the stylus pen 20 comes into contact is expressed by the following expression (10).

ite = V × 1 / √ {(R + Z) ² + 1 / (2π · f · Cte) ² } (10)

  The detection current ipen that flows when the stylus pen 20 comes into contact is expressed by the following expression (11).

ipen = V × 1 / √ {R ² + 1 / (2π · f · Cpen) ² } (11)
It is represented by

  First, a low frequency signal of 100 KHz is applied to the transparent conductive film 32 by the oscillator 3, and a current flowing through the transparent conductive film 32 when the hand holding the stylus pen 20 contacts the panel unit 2 is detected by the detection circuit 4. Let it be detected. Here, regarding the resistance between two opposing sides forming the rectangular extension of the transparent conductive film 32 to which the potential is applied, that is, between the two sets of ends, the resistance in the x direction is Rx, and the resistance in the y direction is Ry. And When a low frequency signal of 100 KHz is given, a detection current for a hand touch is given by the following equations (12) and (13). Here, ixl00te is the current value in the x-axis direction with respect to hand contact when a low frequency signal of 100 KHz is given, that is, the current detected by the ammeter at the −x side end (−x side current value related to the hand). ) And the current (+ x side current value associated with the hand) detected by the ammeter at the + x side end. iyl00te represents the sum of the current value in the y-axis direction with respect to hand contact when a low-frequency signal of 100 KHz is given, that is, the current value at the + y side end and the current value at the −y side end.

ix100te = V × 1 / √ {(Rx + Z) ² + 1 / (2π × 100,000 × Cte) ² } (12)

iyl00te = V × 1 / √ {{(Ry + Z) ² + 1 / (2π × 100,000 × Cte) ² } (13)

  Next, a low frequency signal of 120 KHz is applied to the transparent conductive film 32 by the oscillator 3, and a current flowing through the transparent conductive film 32 when the hand holding the stylus pen 20 contacts the panel unit 2 is detected by the detection circuit 4. 4 to detect. When a low frequency signal of 120 KHz is given, the detection current for hand contact is given by the following equations (14) and (15). Here, ixl20te indicates the sum of the -x side current related to the hand and the + x side current value related to the hand when a low frequency signal of 120 KHz is given. iyl20te indicates the sum of the + y side current value for the hand and the -y side current value for the hand when a low frequency signal of 120 KHz is applied.

ixl20te = V × 1 / √ {(Rx + Z) ² + 1 / (2π × 120,000 × Cte) ² } (14)

iyl20te = V × 1 / √ {(Ry + Z) ² + 1 / (2π × 120,000 × Cte) ² } (15)

  Next, the position detection unit 11 of the control unit 5 virtually calculates a detection current related to the hand when a 2 MHz high frequency signal is given from a current value detected when the 100 KHz and 120 KHz low frequency signals are given. And estimate. As described above, the range of the low-frequency signal in the present invention is a range in which the current component by the stylus pen 20 is cut off by the high-pass filter. When a low-frequency signal is applied, the current component by the stylus pen 20 is cut off, so that the detected current in this case is considered to be caused only by hand contact. Therefore, Rx + Z and Cte are obtained from the equations (12) and (14), and Ry + Z and Cte are obtained from the equations (13) and (15) by measuring the detection current in the low frequency signal of 100 KHz and 120 KHz.

  Furthermore, the current of the detection current relating to the hand when a high frequency signal of 2 MHz is given is given by the following equations (16) and (17). Here, ix2Mte indicates the sum of the −x side current related to the hand and the + x side current value related to the hand when a high frequency signal of 2 MHz is applied. iy2Mte represents the sum of the + y side current value associated with the hand and the −y side current value associated with the hand when a 2 MHz high frequency signal is applied.

ix2Mte = V × 1 / √ {(Rx + Z) ² + 1 / (2π × 2000000 × Cte) ² } (16)

iy2Mte = V × 1 / √ {(Ry + Z) ² + 1 / (2π × 2000000 × Cte) ² } (17)
As described above, if Rx + Z, Ry + Z, and Cte are obtained, ix2Mte and iy2Mte are obtained from equations (16) and (17). That is, ix2Mte and iy2Mte are functions of ixl00te, iyl00te, ixl20te, and iyl20te, respectively.

  Next, the detection circuit 4 detects the stylus pen 20 and the current relating to the hand holding the stylus pen 20 when a 2 MHz high frequency signal is actually applied to the transparent conductive film 32. Then, from the actual current detected when the 2 MHz high frequency signal is applied, the detection current related to the hand when the virtually obtained 2 MHz high frequency signal is applied is subtracted, and when the 2 MHz high frequency signal is applied A detection current (stylus pen detection current) related to the stylus pen 20 is calculated. Specifically, the detection currents relating to the stylus pen 20 and the hand holding the stylus pen 20 when 2 MHz is actually applied to the transparent conductive film 32 are given by the following equations (18) and (19). Here, ix2M represents the sum of the -x side current and the + x side current value associated with the stylus pen 20 and the hand when a high frequency signal of 2 MHz is applied. iy2M indicates the sum of the + y side current value and the −y side current value related to the stylus pen 20 and the hand when a low frequency signal of 2 MHz is given.

  ix2M = ix2Mte + ix2Mpen (18)

  iy2M = iy2Mte + iy2Mpen (19)

  Accordingly, a value obtained by subtracting the current component related to the hand from the measured current value is obtained as the current component related to the stylus pen 20, and the detection current related to the hand and the detection current related to the stylus pen 20 are separated. Then, the coordinates of the contact position of the stylus pen 20 are detected from the detected current related to the stylus pen 20 when the calculated high-frequency signal of 2 MHz is given.

  FIG. 9 is a flowchart showing an operation processing flow of the information input device 50. This operation process is controlled by the control unit 5. When the control unit 5 receives an input instruction from the operation unit 6, the process proceeds to step A1.

  In step A1, a low frequency signal of 100 KHz is applied to the transparent conductive film 32 by the oscillator 3.

  In step A2, the current flowing through the transparent conductive film 32 is detected by the detection circuit 4 when the hand holding the stylus pen 20 comes into contact.

  In Step A3, a low frequency signal of 120 KHz is applied to the transparent conductive film 32 by the oscillator 3.

  In step A4, the detection circuit 4 detects the current flowing through the transparent conductive film 32 when a hand holding the stylus pen 20 comes into contact.

  In step A5, the position detection unit 11 virtually calculates and estimates a detection current relating to a hand when a 2 MHz high frequency signal is applied from a current value detected when the 100 kHz and 120 KHz low frequency signals are applied. To do.

  In step A6, the detection circuit 4 detects the current when the hand holding the stylus pen 20 and the stylus pen 20 comes into contact with the panel unit 2 while the high frequency signal of 2 MHz is actually applied from the oscillator 3 to the transparent conductive film 32. Is done.

  In Step A7, the detection current related to the hand when the 2 MHz high frequency signal calculated in Step A5 is applied is subtracted from the actual detection current when the 2 MHz high frequency signal is applied to the transparent conductive film 32, and the 2 MHz high frequency signal is output. A detection current related to the stylus pen 20 when a signal is given is calculated.

  In step A8, the coordinates of the contact position of the stylus pen 20 are detected from the detected current detected in step A7, and the process ends.

<Specific example>
Specific examples are shown below. FIG. 10 is a plan view schematically showing the panel unit 2 in a state where the stylus pen 20 and the hand are in contact with each other. Further, FIG. 10 shows the positions of the end portions (+ x, −x, + y, −y) orthogonal to each other while forming the rectangular extension of the transparent conductive film 32. FIG. 10 shows a state in which the stylus pen 20 is placed at the center of the panel unit 2 and the hand is in contact with the stylus pen 20 in the + x direction and the −y direction. If the distance between the −x side end and the + x side end is a, and the distance between the + y side and the −y side end is b, the distance from the −x side end to the hand contact position and the hand The hand is in contact with the position where the ratio of the distance from the contact position to the + x side end is (3a / 4) :( a / 4). Further, the hand touches the position where the ratio of the distance from the + y side end to the hand contact position and the distance from the hand contact position to the −y side end is (3b / 4) :( b / 4). doing.

  Here, the current (−x side current value) detected by the ammeter at the −x side end and the current at the + x side when a low frequency signal of distances a, b and 100 KHz is applied to the transparent conductive film 32. The ratio of the current detected by the meter (+ x side current value), and the current detected by the ammeter at the + y side end (+ y side current value) and the current detected by the ammeter at the −y side end ( The coordinates of the hand can be detected by determining the ratio to the (−y side current value). In the case of FIG. 10, the ratio between the −x side current value and the + x side current value and the ratio between the + y side current value and the −y side current value are 1: 3, respectively. Further, the sum of the −x side current value and the + x side current value is ixl00te, and the sum of the + y side current value and the −y side current value is iyl00te.

  Next, a low frequency signal of 120 KHz is applied to the transparent conductive film 32, and ixl20te and iyl20te are calculated similarly. Here, when ixl00te = 29.4 μA, iyl00te = 28.7 μA, ixl00te = 30.5 μA, and iyl20te = 29.7 μA, Rx + 10 is obtained from the above equations (12), (13), (14), and (15). Z = 30 KΩ, Ry + Z = 31 KΩ, and Cte = 100 pF. Substituting these values into the above equations (16) and (17) yields ix2Mte = 33.3 μA and iy2Mte = 32.2 μA.

  Here, when a high frequency signal of 2 MHz is applied to the transparent conductive film 32, the -x side current value related to the hand is ix2Mte left, the + x side current value related to the hand is ix2Mte right, and the + y side current value related to the hand is iy2Mte. Assuming that the -y side current value related to the upper hand is lower than iy2Mte, the ratio between the -x side current value and the + x side current value and the ratio between the + y side current value and the -y side current value are 1: 3, respectively. Therefore, ix2Mte left = 8.3 μA, ix2Mte right = 25.0 μA, iy2Mte upper = 8.0 μA, iy2Mte lower = 24.0 μA.

  Next, by subtracting these values from the stylus pen 20 detected when the high frequency signal of 2 MHz is actually applied to the transparent conductive film 32 and the current relating to the hand, the stylus pen when the high frequency signal of 2 MHz is applied. The detection current according to 20 is obtained as follows. Here, when a high-frequency signal of 2 MHz is applied to the transparent conductive film 32, the -x side current value related to the stylus pen 20 and the hand is ix2M left, the + x side current value related to the stylus pen 20 and the hand is ix2M right, and the stylus. The + y side current value related to the pen 20 and the hand is set to iy2M, and the −y side current value related to the stylus pen 20 and the hand is set to iy2M below. Here, ix2M left = 18.3 μA, ix2M right = 35.0 μA, iy2M upper = 17.9 μA, and iy2M lower = 33.9 μA are detected.

  Further, when a high frequency signal of 2 MHz is applied to the transparent conductive film 32, the -x side current value related to the stylus pen 20 is ix2Mpen left, the + x side current value related to the stylus pen 20 is ix2Mpen right, and + y related to the stylus pen 20. If the side current value is on iy2Mpen and the -y side current value on the stylus pen 20 is on iy2Mpen, the ix2Mpen left, ix2Mpen right, iy2Mpen up, and iy2Mpen down are obtained by the following equations.

(Ix2Mpen left) = (ix2M right) − (ix2Mte left) = 10.0 μA
(Ix2Mpen right) = (ix2M left) − (ix2Mte right) = 10.0 μA
(On iy2Mpen) = (on iy2M) − (on iy2Mte) = 9.9 μA
(Under iy2Mpen) = (under iy2M) − (under iy2Mte) = 9.9 μA.

  Therefore, from (ix2Mpen left) :( ix2Mpen right) = 1: 1, (iy2Mpen top) :( iy2Mpen bottom) = 1: 1, it is detected that the coordinate of the touch position of the stylus pen 20 is the center of the panel unit 2. Is done.

  As described above, in the information input device 50 according to the first embodiment, in the pen input in which the hand and the stylus pen are simultaneously in contact with the panel, signals of two types of high and low frequencies are transmitted to the transparent conductive film 32 of the panel unit 2. Are sequentially applied, and the contact position of the stylus pen 20 is appropriately detected based on the difference in the detected current. For this reason, accurate input using the stylus pen 20 is possible. Further, with such a configuration, the configuration of the stylus pen 20 is complicated, and the load due to the weight of the stylus pen 20 is not increased, and comfortable character input that does not hinder operability is possible.

[Second Embodiment]
In the second embodiment, a two-color pen is realized by inserting a plurality of resistors having different resistance values into the stylus pen and providing a button for switching the current flowing through the stylus pen.

  FIG. 11 is a block diagram illustrating a functional configuration of an information input device 50A according to the second embodiment. FIG. 12 is a diagram schematically showing a cross section of the structure of the stylus pen 20A according to the second embodiment. Since the functional configuration of the second embodiment is similar to that of the above-described first embodiment, the same components are denoted by the same reference numerals, description thereof is omitted, and different configurations will be described.

  As shown in FIG. 11, the stylus pen 20 has a stylus pen 20A having a different configuration, the control unit 5 has a functional configuration and a color change unit 12 is added to the control unit 5A, and the panel body 1 has the control unit 5A. Each panel body portion 1A is changed. The stylus pen 20 </ b> A is roughly configured by a pen body portion 21, a pen tip portion 22, a conductive portion 23 made of metal, a connection terminal 24, a connection cable 25, a first resistor 46, a second resistor 47, and a color switching button 48.

  The first resistor 46 and the second resistor 47 are provided between the pen tip portion 22 and the connection terminal 24 and have different resistance values. For example, when the resistance value of the first resistor 46 is set in the range of 25 kΩ to 35 kΩ, the range of the current value flowing through the first resistor 46 is 21.2 μA to 18.7 μA, and the resistance value of the second resistor 47 is 50 kΩ to When set in the range of 60 kΩ, the range of the current value flowing through the second resistor 47 is 15.6 μA to 13.8 μA.

  A color is displayed on the surface of the color switching button 48, and when the selected button is pressed, the spring-like members electrically connected to the first and second resistors 46 and 47 are appropriately deformed. The connection state of the first and second resistors 46 and 47 is changed, so that the color of characters and diagrams can be changed. Specifically, the pen tip 22, the first resistor 46, and the connection terminal 24 are electrically connected in series by the color switching button 48, and the pen tip 22 and the second resistor 47 are connected. The second connection state in which the terminal 24 is electrically connected in series is selectively set.

  The color changing unit 12 changes the color of a character or a diagram input by the stylus pen 20 </ b> A based on the magnitude of the stylus pen detection current that is switched according to the state setting by the color switching button 48.

  According to the present embodiment, it is possible to input characters and diagrams of a plurality of colors with a single stylus pen.

[Third embodiment]
In the third embodiment, a plurality of resistors having different resistance values are inserted into the stylus pen, and a button for switching the current flowing through the stylus pen is provided to erase characters and diagrams.

  FIG. 13 is a block diagram illustrating a functional configuration of an information input device 50B according to the third embodiment. FIG. 14 is a diagram schematically showing a cross section of the structure of the stylus pen 20B according to the third embodiment. Since the functional configuration of the third embodiment is similar to that of the first embodiment described above, the same components are denoted by the same reference numerals, description thereof is omitted, and different configurations will be described.

  As shown in FIG. 13, the stylus pen 20 has a stylus pen 20B having a different configuration, the control unit 5 has a functional configuration, and the state switching unit 13 is added to the control unit 5B. The panel body unit 1 has the control unit 5B. Each is changed to the panel body 1B provided. The stylus pen 20B is schematically configured by a pen body portion 21, a pen tip portion 22, a metal conductive portion 23, a connection terminal 24, a connection cable 25, a first resistor 86, a second resistor 87, a switching button 88, and an eraser button 89. Is done.

  The first resistor 86 and the second resistor 87 are provided between the pen tip portion 22 and the connection terminal 24, and have different resistance values. For example, when the resistance value of the first resistor 86 is set in the range of 25 kΩ to 35 kΩ, the range of the current value flowing through the first resistor 86 is 21.2 μA to 18.7 μA, and the resistance value of the second resistor 87 is 50 kΩ to When set in the range of 60 kΩ, the range of the current value flowing through the second resistor 87 is 15.6 μA to 13.8 μA.

  Here, when the switch button 88 is pressed and the eraser button 89 is not pressed, the pen tip 22, the first resistor 86, and the connection terminal 24 are set in a first connection state in which they are electrically connected in series. If the switch button 88 is not pressed and the eraser button 89 is pressed, the pen tip portion 22, the second resistor 87, and the connection terminal 24 are set in a second connection state that is electrically connected in series. That is, the switch button 88 and the eraser button 89 are selectively set to the first and second connection states.

  The state switching unit 13 inputs or deletes characters or a diagram based on the magnitude of the stylus pen detection current that is switched according to the state setting by the switch button 88 and the eraser button 89.

  According to the present embodiment, it is possible to input and erase characters and diagrams with a single stylus pen.

<Modification>
As mentioned above, although embodiment of this invention was described, this invention is not limited to the thing of the content demonstrated above.

  For example, in the above embodiment, the transparent conductive film 32 has the reference position to which the potential is applied at both ends in two orthogonal directions, that is, at the four ends, but the reference position is aligned along the uniaxial direction. Two positions at both ends may be used, and the position where the stylus pen and the hand touch each other may be detected in a one-dimensional direction. Further, the reference position may be set to a portion that enters the inside from the end of the transparent conductive film 32 without setting the end of the transparent conductive film 32.

  In the second embodiment, the stylus pen enables input of two colors, but may be a stylus pen capable of inputting characters and diagrams of three or more colors having three or more resistors.

It is a block diagram which illustrates functional composition of information input device 50 concerning a 1st embodiment of the present invention. 2 is a diagram schematically showing a cross section of the structure of the panel unit 2 and the stylus pen 20. FIG. It is the top view which looked at the transparent conductive film 32 from the upper part. It is a figure which illustrates the input mode of the information in the panel part. It is a figure for demonstrating the detection method of the input coordinate of information. It is a figure for demonstrating the detection method of the input coordinate of information. It is a figure which shows an example of the equivalent circuit of the panel part 2 and a human body. It is a figure which shows the panel part 2 of this embodiment, and the equivalent circuit of a human body. 5 is a flowchart showing an operation processing flow of the information input device 50. It is the top view which showed roughly the stylus pen 20 and the panel part 2 of the state which the hand contacted. It is a block diagram which illustrates functional composition of information input device 50A concerning a 2nd embodiment. It is a figure which shows typically the cross section of the structure of stylus pen 20A which concerns on 2nd Embodiment. It is a block diagram which illustrates functional composition of information input device 50B concerning a 3rd embodiment. It is a figure which shows typically the cross section of the structure of stylus pen 20B which concerns on 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main-body part 2 Panel part 3 Oscillator 4 Detection circuit 5, 5A, 5B Control part 11 Position detection part 12 Color change part 13 State switching part 20, 20A, 20B Stylus pen 32 Transparent conductive film 50, 50A, 50B Information input device

Claims (3)

A stylus pen for entering text or line diagrams,
A panel portion having an insulating film and a conductive film;
A signal applying unit that sequentially applies first and second frequency signals having a frequency lower than a predetermined frequency and a third frequency signal having a frequency higher than the predetermined frequency to a plurality of reference positions of the conductive film. When,
A current detector for detecting a current flowing through each of the reference positions due to capacitive coupling generated in response to contact of the stylus pen and an operator's hand with the insulating film;
From the first and second currents detected by the current detection unit when the first and second frequency signals are applied to the plurality of reference positions, respectively, the first and second currents are detected with respect to the plurality of reference positions. A third current generated according to contact of the operator's hand detected by the current detection unit when the third frequency signal is applied is virtually calculated, and the third current is calculated with respect to the plurality of reference positions. Based on the difference between the fourth current and the third current generated in response to simultaneous contact of the stylus pen and the operator's hand detected by the current detection unit when a three-frequency signal is applied, A position detection unit for detecting a contact position of the stylus pen with respect to the panel unit;
Equipped with a,
The conductive film is, the information input device which is characterized that you have been arranged as a single electrode to cover the entire surface of all pixels of the panel portion. The information input device according to claim 1,
The stylus pen is
A tip portion for contacting the insulating film;
A grounding terminal for grounding,
A first resistor and a second resistor having different resistance values between the tip portion and the grounding terminal;
A first connection state in which the tip portion, the first resistor, and the grounding terminal are electrically connected in series, and the tip portion, the second resistor, and the grounding terminal are electrically connected in series. A state setting unit for selectively setting the second connection state to be performed;
Have
A color changing unit that changes a color of a character and / or a diagram input by the stylus pen based on the difference that is switched according to a state setting by the state setting unit;
An information input device further comprising: The information input device according to claim 1,
The stylus pen is
A tip portion for contacting the insulating film;
A grounding terminal for grounding,
A first resistor and a second resistor having different resistance values between the tip portion and the grounding terminal;
A first connection state in which the tip portion, the first resistor, and the grounding terminal are electrically connected in series, and the tip portion, the second resistor, and the grounding terminal are electrically connected in series. A state setting unit for selectively setting the second connection state to be performed;
Have
Based on the difference that is switched according to the state setting by the state setting unit, a state in which characters and / or diagrams are input by the stylus pen and a state in which characters and / or diagrams are deleted by the stylus pen Switching state switching unit,
An information input device further comprising:

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