JP2011065450A - Position detector and pointer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a signal with high intensity from a pointer even at the periphery of the center of an enlarged position detection area. <P>SOLUTION: A position detector includes a pointer 1, which includes: a first coil 11; a second coil 12 arranged at a predetermined distance from the first coil 11; and a signal transmission part 14 transmitting induced current, which occurs when the second coil 12 detects an excitation signal, to the first coil 11. An induced voltage generated by the second coil 12 is transmitted to the first coil 11, and the first coil 11 transmits a pointing signal to a loop coil. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to, for example, a position detection device and a position indicator that detect the position of a position indicator in a predetermined area, and a user draws coordinates, graphics, and the like on the position detection device using the position indicator. The present invention relates to a position detection device and a position indicator that are suitable for application when performing an input operation.

  2. Description of the Related Art Conventionally, a position detection device has been developed as an input device used when performing photo processing or illustration creation on a computer device. In general, the position detection device is composed of a substantially flat tablet and a pen-shaped position indicator operated by the user on the tablet.

  As the position detection device, for example, there is a position detection device using an electromagnetic induction method. A plurality of loop coils are arranged in each of the X direction and the Y direction in the tablet included in the position detection device, and a resonance circuit is provided in the position indicator. A position detection area for detecting a coordinate position indicated by the position indicator is set on the upper surface of the tablet. The position detection region may be referred to as a “position detection surface” for inputting the position indicated by the electromagnetic induction type position indicator to the position detection device. And a tablet transmits / receives the electromagnetic wave of the predetermined frequency by an electromagnetic induction effect | action with respect to the resonance circuit in a position indicator for every loop coil switched sequentially, and detects the indication position of a position indicator.

As this type of apparatus, for example, the techniques disclosed in Patent Documents 1 and 2 have been put into practical use.
Patent Document 1 discloses a position detection device that obtains a specified position of a position indicator by an induced voltage generated in a loop coil.
Patent Document 2 discloses a position indicator that encodes information corresponding to an operation represented by a continuous amount and sends it back to the position detection device.

  According to the techniques disclosed in Patent Documents 1 and 2, by providing a resonance circuit in the position indicator and transmitting and receiving electromagnetic waves between the tablet and the position indicator, the position on the tablet indicated by the position indicator is determined. To detect. Then, by making the position indicator cordless and not providing a battery, a position indicator and a position detection device with extremely good operability can be realized.

  However, in recent years, liquid crystal display devices have been put into practical use, and there has been an increasing demand for position detection devices in which the position detection device described above is combined with a liquid crystal display device so that a place to be drawn can be directly input with a pen. When the position detection device is used in such a form, there is a problem that the sensor coil of the tablet cannot be arranged on the front surface of the liquid crystal panel. Here, in the conventional device in which the liquid crystal display device and the tablet are integrated, the sensor portion for forming the loop coil described above is placed on the back surface of the liquid crystal. For this reason, it is necessary to disassemble the liquid crystal panel once completed and then incorporate the sensor unit, which increases the number of work steps and makes it difficult to change the liquid crystal panel. Therefore, in recent years, there has been an increasing demand for making the sensor part of the tablet transparent and disposing it in front of the liquid crystal panel. As a transparent conductive material, an ITO film is widely known, but since the resistance value is high, it is impossible to transmit power by this.

  As a method for solving such a problem, there is a proposal of providing a transmission exciting coil on the outer periphery of the position detection region of the tablet. For example, Patent Document 3 discloses an example in which an excitation coil is provided on the outer periphery of the tablet position detection region.

  If a tablet having an excitation coil on the outer periphery is used, it is not necessary to incorporate a battery or the like in the main body of the position indicator, and strong electric power can be supplied by the outer periphery coil. Further, since the coil for position detection may be dedicated for reception, it can be made transparent.

JP-A-63-70326 Japanese Patent Laid-Open No. 7-175572 JP-A-5-88811

  However, as the position detection area becomes larger, the signal detected near the center becomes weaker, and in order to obtain a sufficiently strong signal even in the center of the position detection area, the power supplied from the outer coil must be very large. . For this reason, there exists a problem of shortening the use time of a battery especially for mobile uses, such as a notebook PC.

  In the present invention, it is not necessary to provide a battery or the like in the position indicator for such problems, and the sensor coil of the tablet can be arranged on the front surface of the liquid crystal panel, and also in mobile applications such as notebook PCs. An object of the present invention is to realize a position detection device that does not significantly affect the battery usage time.

The position detection device according to the present invention comprises a tablet provided with a plurality of loop coils in the position detection region, an excitation coil wound around the outer periphery of the position detection region, and a substantially bar-shaped position indicator.
A position detection device that sends a signal from an excitation coil to a position indicator and detects signals from the position indicator by a plurality of loop coils,
The position indicator includes a first coil disposed at one end close to the position detection region, a second coil disposed away from the position indicator, and a signal connecting the first coil and the second coil. An electrical signal that is composed of a transmission unit and is induced in the second coil by a signal from the excitation coil is transmitted to the first coil via the signal transmission unit, and a signal is transmitted from the first coil to the loop coil. It is characterized by being sent out.
Furthermore, the first coil and the second coil are connected in parallel or in series, and may constitute a resonance circuit.

  By doing so, the coil that is away from the position detection area receives the signal sent from the excitation coil, and sends the signal from the coil that is used in the vicinity of the position detection area to the loop coil. The position of the vessel will be detected.

According to the present invention, the position indicator is provided with a signal detection coil at a position apart from the position detection surface separately from the position indication signal transmission coil, and the electrical signal generated by the signal detection coil is indicated by the position indicator. Since the signal is transmitted to the signal transmission coil, it is possible to detect a strong signal even if the position indicator is in the center of the position detection region. For this reason, the electric power sent out from the excitation coil of the outer periphery can be suppressed to a low level, and the usage time of the battery can be maintained long even in mobile applications.
In addition, since the signal from the position indicator is transmitted by the excitation coil provided on the outer periphery of the position detection region, a sensor for detecting the signal from the position indicator is formed by a transparent electrode such as an ITO film formed on the glass surface. The sensor coil of the tablet can be arranged on the front surface of the liquid crystal panel. In addition, it is not necessary to provide a battery or the like in the position indicator, and an easy-to-use position detection device can be realized.

It is a schematic block diagram of the position detection apparatus in one embodiment of this invention. It is a block diagram which shows the internal structural example of the position indicator in one embodiment of this invention. It is explanatory drawing which shows the example of arrangement | positioning of the 1st and 2nd coil with which the position indicator in one embodiment of this invention is provided. It is explanatory drawing which shows the example of the three-dimensional structure of the tablet part in one embodiment of this invention. It is a block diagram which shows the internal structural example of the tablet in one embodiment of this invention. It is explanatory drawing which shows the example of the magnetic field distribution by the exciting coil in one embodiment of this invention. It is explanatory drawing which shows the example of the basic principle for the position indicator in one embodiment of this invention to transmit a strong position indication signal to a sensor glass also in a center area | region. It is a block diagram which shows the internal structural example of the position indicator in other embodiment of this invention.

  Hereinafter, an embodiment of a position detection device of the present invention will be specifically described with reference to the accompanying drawings. However, the present invention is not limited to this embodiment.

<Configuration of position detection device>
FIG. 1 is an external perspective view of the position detection device 10 of the present embodiment.
The position detection device 10 includes a substantially bar-shaped position indicator 1 and a flat tablet 2. The position indicator 1 has a pen shape and includes a pen tip portion 1a and a tail portion 1b. A first coil 11 is stored in the pen tip portion 1a, and a second coil 12 is stored in the tail portion 1b (see FIG. 3 described later).

  The tablet 2 includes a position detection area 2a and a surrounding outer frame 2b. The tablet 2 can detect the coordinates of the position indicated by the position indicator 1 on the position detection area 2a formed inside the outer frame 2b.

  The tablet 2 is connected to an external computer device (not shown). The tablet 2 detects the coordinates of the position designated by the position indicator 1 (hereinafter referred to as “designated position”), and outputs information related to the designated position to the computer device. The computer device displays a line drawing or the like corresponding to the coordinates input from the tablet 2 on a screen of a liquid crystal panel 32 (see FIG. 4 described later) used as a liquid crystal display device.

  In this example, the pen tip 1a is used in the vicinity of the position detection area 2a. The pen nib 1a is used for drawing a diagram or selecting a predetermined command. On the other hand, the proximity of the tail portion 1b to the position detection region 2a is used for erasing a previously drawn diagram.

  FIG. 2 shows an internal configuration example of the position indicator 1.

The position indicator 1 includes a first coil 11 in the pen tip portion 1a and a second coil 12 in the tail portion 1b. Both the first coil 11 and the second coil 12 are formed by winding around a ferrite core (not shown), and are arranged at a predetermined distance apart. In the present embodiment, the first coil 11 and the second coil 12 are used as a composite coil connected in parallel. Further, the position indicator 1 includes a capacitor 13, and the first coil 11, the second coil 12, and the capacitor 13 are from an exciting coil 30 (see FIG. 4 described later) disposed on the outer periphery of the tablet 2. by a signal consisting of the magnetic field of a predetermined frequency f _0, it constitutes a resonant circuit resonating. In this embodiment, the signal generated by the magnetic field having the frequency f ₀ is hereinafter referred to as an excitation signal.

  Further, the position indicator 1 transmits an induced current generated when the first coil 11 detects the excitation signal to the second coil 12, and the second coil 12 detects the excitation signal from the excitation coil 30. A signal transmission unit 14 for transmitting the induced current generated in the case of the first coil 11 to the first coil 11. In this example, a conducting wire is used as the signal transmission unit 14.

Specifically, when the first coil 11 is used in the vicinity of the central region of the position detection region 2a, the induced current generated in the second coil 12 is transmitted to the first coil 11. Then, the first coil 11 sends a signal due to the magnetic field to the tablet 2 (loop coil 41 (see FIG. 5 described later)). In this embodiment, a signal based on a magnetic field sent from the first coil 11 to the tablet 2 is used as a position indication signal.
On the other hand, in a use state where the first coil 11 is used in the vicinity of the peripheral portion other than the central region of the position detection region 2a, the induced current generated in the second coil 12 by the magnetic field from the exciting coil 30 Since the induced current generated in the first coil 11 is large, a position instruction signal is sent from the first coil 11 to the tablet 2.

  Next, the basic structure of the position indicator 1 will be described. A power extraction circuit 15 that extracts power from the induced voltage generated in the resonant circuit and supplies power to each circuit described later, and a predetermined timing signal is generated by the induced voltage generated in the resonant circuit by the magnetic field radiated from the tablet 2. A timing extraction circuit 16 for detection is provided. The timing extraction circuit 16 extracts a timing signal from the continuous emission time and period of the excitation signal from the tablet 2. That is, the excitation signal from the tablet 2 is continuously radiated for a predetermined period or longer, and then intermittently radiated with a predetermined period sufficiently shorter than the predetermined period and with a predetermined duration, so that the timing signal is extracted. Is.

  The position indicator 1 also includes a delay circuit 17 that delays the timing signal extracted by the timing extraction circuit 16 for a predetermined time, and a continuous signal detection that detects a continuous signal based on the timing signal extracted by the timing extraction circuit 16. A circuit 18 is provided.

  The continuous signal detection circuit 18 includes a detection circuit made up of a diode, an integration circuit made up of a resistor and a capacitor, and a waveform shaping circuit made up of a resistor and a buffer amplifier. The timing signal input to the continuous signal detection circuit 18 is rectified by a diode, integrated by a resistor and a capacitor, and further shaped by a resistor and a buffer amplifier. Detect as a pulse signal.

Further, the position indicator 1 includes a writing pressure / time conversion circuit 19 that detects an operation expressed by a continuous amount, in this example, a writing pressure of the pen tip 1a and converts it into digital data. The writing pressure / time conversion circuit 19 is configured by a differential circuit including a variable resistance element and a capacitor whose resistance value changes according to the writing pressure (specifically, the resistance value increases as the writing pressure increases). . This digital data is output to the counter 20 as a writing pressure signal.
Instead of the variable resistance element, a capacitor whose capacitance value changes according to writing pressure or an inductance element whose induction value changes according to writing pressure may be used.

  The position indicator 1 includes a counter 20 that counts the frequency of the induced current generated in the resonance circuit by the excitation signal radiated from the tablet 2 while the signal is output from the writing pressure / time conversion circuit 19. A P / S conversion circuit 21 that converts data into serial data and a switch 22 that controls on / off according to writing pressure information input from the P / S conversion circuit 21 are provided.

  The P / S conversion circuit 21 intermittently emits an excitation signal from the tablet 2 at a constant cycle, and sequentially sends the count value of the counter 20 to the resonance circuit in synchronization with the timing signal extracted by the timing extraction circuit 16. The resonance characteristic of the resonance circuit is changed.

FIG. 3 shows an arrangement example of the first coil 11 and the second coil 12 provided in the position indicator 1.
When the position indicator 1 is used in the position detection region 2a of the tablet 2, the first coil 11 provided in the position indicator 1 is close to the position detection surface.
Note that the first coil 11 is disposed on the pen tip 1 a as one end of the position indicator 1 in order to correctly detect the coordinate position of the position indicator 1.

  On the other hand, the second coil 12 is disposed in the tail portion 1 b that is disposed at a predetermined distance from the first coil 11. The second coil 12 disposed in the tail portion 1b is provided at a position away from the first coil 11 upward with respect to the position detection surface in a normal use state. The first coil 11 and the second coil 12 are electrically connected by a signal transmission unit 14 that transmits an induced current based on the excitation signal received from the tablet 2 to each other. In a normal use state, the signal transmission unit 14 transmits an electrical signal (inductive current) induced in the second coil 12 to the first coil 11. Then, a magnetic field (position indication signal) is sent to the loop coil 41 (see FIG. 5 described later) by the first coil 11 close to the position detection region 2a.

  FIG. 4 shows the three-dimensional structure of the tablet part.

  The tablet 2 includes a liquid crystal panel 32 and a sensor glass 33. The sensor glass 33 is formed by bonding two pieces of glass having a thickness of about 0.4 mm, and a pattern of a loop coil 41 (see FIG. 5) to be described later is formed on each glass by an ITO film. That is, X1-X40 is formed on one glass, and Y1-Y30 patterns are formed on the other glass by etching. These glasses are made so that the surfaces of the ITO film face each other and a transparent insulating sheet is sandwiched between them.

The tablet 2 includes flexible substrates 34 and 35 based on a polyimide material. The flexible substrate 34 is connected to the pattern of each line of X1 to X40 of the sensor glass 33, and forms a folded portion for forming a loop. Similarly, the flexible substrate 35 is also connected to the pattern of each line of X1 to X40 of the sensor glass 33 and connected to the selection circuit 42. Such a configuration is the same for the loop coils Y1 to Y30. And the exciting coil 30 is wound around the outer periphery of the position detection area 2a.
A shield plate 31 having appropriate conductivity is provided on the back surface of the liquid crystal panel 32 in order to eliminate the influence of surrounding metal objects and noise.

  FIG. 5 shows a configuration example of the tablet 2.

  The tablet 2 includes a plurality of loop coils 41 arranged substantially in parallel in a predetermined direction as X1 to X40 and Y1 to Y30 in the X axis direction and the Y axis direction, respectively. The position detection area 2a constituted by the loop coil 41 is integrated with the liquid crystal panel 32 (see FIG. 4), and the dimensions and arrangement pitch of the loop coil 41 are set so that the position detection area 2a coincides with the display area of the liquid crystal panel 32. Is determined. The plurality of loop coils 41 receive a position indication signal that indicates the position of the position indicator 1 from the position indicator 1 in the position detection region 2a. A plurality of loop coils 41 arranged in parallel in a predetermined direction as X1 to X40 and Y1 to Y30 are connected to a selection circuit 42 that selects each loop coil.

The output terminal selected by the selection circuit 42 is connected to an amplification circuit 43, which is connected to a band pass filter 44 having f ₀ as a center frequency, and the band pass filter 44 is connected to a detection circuit 45. The detection circuit 45 is connected to a sample and hold circuit 46, the voltage held by the sample and hold circuit 46 is connected to the A / D conversion circuit 47, and the output of the A / D conversion circuit 47 is connected to the CPU 48.

The tablet 2 includes an excitation coil 30 wound around the plurality of loop coils 41 so as to surround the outer periphery of the position detection region 2a. In FIG. 5, the exciting coil 30 is illustrated with two turns, but in actuality, the exciting coil 30 is wound with eight to ten or more turns. The excitation coil 30 is connected to the drive circuit 40, drive circuit 40 is connected to an oscillation circuit 49 that oscillates at a frequency f _0. The excitation coil 30 has a function of sending an excitation signal to the position indicator 1.

  The CPU 48 sends control signals to the drive circuit 40, the selection circuit 42, the sample hold circuit 46, and the A / D conversion circuit 47, respectively. The CPU 48 supplies a control signal to the drive circuit 40 and controls transmission of the excitation signal from the excitation coil 30 to be on or off. The CPU 48 detects the position of the position indicator 1 in the position detection area 2a based on the position instruction signal received by the loop coil 41.

Here, the operation in which the tablet 2 detects the position of the position indicator 1 will be described.
When the position indicator 1 is placed in the position detection region 2a by the user's operation, the CPU 48 performs a transmission / reception operation on a plurality of adjacent points where the position indicator 1 is placed from the X-axis loop coil group. Then, the CPU 48 obtains the X coordinate value of the indicated position of the position indicator 1 from the level distribution of the position indicating signal detected by the X axis loop coil group. Subsequently, the CPU 48 performs a transmission / reception operation on a plurality of the vicinity of the position indicator 1 from the Y-axis loop coil group. Then, the CPU 48 obtains the Y coordinate value of the indicated position of the position indicator 1 from the level distribution of the position indicating signal detected by the Y-axis loop coil group. These coordinate detections are performed in the same procedure as in the conventional position detection apparatus.

  Subsequently, the CPU 48 continuously transmits a predetermined time (for example, 1 millisecond) from the exciting coil 30 in order to detect 8-bit writing pressure to the position indicator 1. Thereafter, at the same timing as the coordinate detection, a transmission / reception operation is performed by transmission from the excitation coil 30 and reception of a signal whose level changes for each bit of writing pressure information. This transmission / reception operation is continuously performed, for example, eight times. At this time, the selection circuit 42 selects the nearest loop coil (which may be X-axis or Y-axis) from the position indicator 1 and receives a position indication signal. In this way, the pen pressure information of the position indicator 1 can be detected by the tablet 2.

  Next, the reason why the position indicator 1 can return a strong position indication signal to the tablet 2 even in the central area of the position detection area 2a will be described.

FIG. 6 shows an example of a magnetic field distribution generated by the exciting coil 30. In this type of position detection device, a shield plate 31 may be disposed on the back surface of the position detection region 2a. In this case, of the magnetic field generated from the exciting coil 30, the magnetic field that circulates from behind the detection surface of the position detection region 2 a is blocked by the shield plate 31. Therefore, the magnetic field in the central region of the position detection region 2a becomes extremely weak.
On the other hand, at a certain height from the detection surface in the central region of the position detection region 2a, the magnetic field is relatively stronger than the vicinity of the detection surface of the position detection region 2a due to the characteristics of the magnetic field distribution.

However, since the position indication signal transmitted by the position indicator 1 needs to be detected by the loop coil disposed in the position detection region 2a or the sensor glass 33, the coil included in the position indicator 1 transmits the position indication signal. Therefore, it must be used at a position close to the detection surface of the position detection region 2a.
On the other hand, in the conventional position indicator having one coil, the tablet of the relatively small position detection region receives the magnetic field from the excitation coil and sends the magnetic field signal back to the tablet by the same coil even in the central region, and the tablet 2 loops. There was no problem in detecting the signal with the coil. However, in a tablet having a wide position detection region, the magnetic field received from the excitation coil is weak in the central region, so that the position indication signal from the position indicator 1 becomes extremely weak, and the position indication signal received by the loop coil is It becomes extremely weak. Therefore, when a conventional position indicator is used, the position of the position indicator cannot be detected in a relatively large tablet.

  FIG. 7 shows a basic principle for the position indicator 1 to transmit a strong position indication signal to the sensor glass 33 even in the central region.

  In addition to the first coil 11 used by the tablet 2 to detect coordinates, the position indicator 1 includes a second coil 12 for detecting an excitation signal transmitted by the excitation coil 30. The first coil 11 and the second coil 12 are connected in parallel.

  When the user brings the pen tip portion 1a of the position indicator 1 close to the central region of the position detection region 2a, the tail portion 1b is positioned higher than the detection surface of the position detection region 2a. In the position indicator 1 in the central region, the second coil 12 at a position higher than the detection surface of the position detection region 2a receives an excitation signal stronger than the first coil 11 from the excitation coil 30, and an induced current is generated. . The induced current generated when the second coil 12 is excited is transmitted to the first coil 11 via the signal transmission unit 14, and the first coil 11 can generate a strong magnetic field. Since this magnetic field is sufficiently close to the detection surface of the position detection region 2a, the loop coil 41 is detected as a strong position indication signal generated by the position indicator 1. For this reason, even if the position indicator 1 is placed in the central region, the tablet 2 can accurately detect the position.

  According to the embodiment described above, since it is not necessary to make the excitation signal generated by the excitation coil 30 so strong, there is an effect that the power consumption of the tablet 2 can be suppressed. For this reason, the electric power sent out from the outer periphery excitation coil 30 can be restrained small, and the usage time of a battery can be maintained long also in a mobile use. Further, it is not necessary to provide a battery or the like in the position indicator 1, and the user-friendly position detecting device 10 can be realized.

  The induced current generated in the second coil 12 of the position indicator 1 by the excitation signal transmitted from the excitation coil 30 of the tablet 2 is transmitted to the first coil 11 by the signal transmission unit 14, and A position indication signal corresponding to the magnitude of the induced current generated in the second coil 12 is radiated from the coil 11. For this reason, since a strong position indication signal is radiated even if the position indicator 1 is placed in the center region of the position detection region 2a, the tablet 2 can accurately detect the position of the position indicator 1.

  Further, in the tablet 2, by separating the transmission coil and the reception coil, the loop coil 41, which is the reception coil, can be formed into a relatively high resistance ITO film known as a transparent electrode, which is formed on the glass surface. It becomes possible. Further, since the signal from the position indicator 1 is transmitted by the exciting coil provided on the outer periphery of the position detection region 2a, an ITO film or the like in which a sensor for detecting the signal from the position indicator 1 is formed on the glass surface is used. It can be formed by a transparent electrode. For this reason, the loop coil 41 can be disposed on the front surface of the liquid crystal panel 32. With such a configuration, there is no need to disassemble the liquid crystal panel 32 in the manufacturing process of the tablet 2, and the yield of the tablet 2 is improved.

  In this embodiment, it is also possible to supply power to the position indicator 1 by sending an excitation signal from the excitation coil 30 to the position indicator 1. This is because the second coil 12 is excited by an excitation signal from the excitation coil 30 to generate an induced voltage, and power can be extracted and stored by the power supply extraction circuit 15. For this reason, a circuit such as an internal IC can be operated based on the extracted power. Further, it is not necessary to provide a battery or the like in the position indicator 1, the position indicator 1 can be reduced in weight, and a plurality of pieces of information can be set in the position indicator 1, so the instructions from the tablet 2 are followed. There is an effect that complicated processing can be performed.

  In the position indicator 1 according to the above-described embodiment, the first coil 11 and the second coil 12 are arranged in parallel to configure a resonance circuit. However, the resonance circuit may be configured by connecting in series, It does not necessarily have to be a resonant circuit. Further, it is preferable that the position of the upper coil of the two coils is determined so that the excitation signal is detected most strongly in the central region according to the size of the tablet and the material of the shield plate.

  FIG. 8 is a block diagram illustrating another configuration example of the position indicator 1. In the following description, the same reference numerals are given to the portions corresponding to FIG. 2 described in the above-described embodiment, and detailed description thereof is omitted.

FIG. 8A shows an internal configuration example of the position indicator 1 when the first coil 11 and the second coil 12 are connected in series.
Even in this case, the first coil 11, the second coil 12 and the capacitor 13 can form a resonance circuit.

FIG. 8B shows an internal configuration example of the position indicator 1 when the signal transmission unit 14 includes an amplification unit 51 that amplifies the intensity of the induced voltage.
In this example, an amplifier is used as the amplifying unit 51, for example. In this case, the position indicator 1 can amplify the intensity signal and transmit it to the first coil 11 even if the intensity of the excitation signal received by the second coil 12 is slight. For this reason, there is an effect that more stable position detection can be performed. The first coil 11 and the second coil 12 constitute a resonance circuit, and the induced voltage obtained by the resonance circuit of the second coil 12 is amplified by the amplification unit 51 and the resonance of the first coil 11 is achieved. Is transmitted to the circuit.

In the present embodiment, the excitation signal from the excitation coil 30 is received by the second coil 12, an induced current is generated, the induced current is transmitted to the first coil 11, and the position from the first coil 11 is changed. An instruction signal is sent to the tablet 2.
Further, when the second coil 12 is used close to the position detection region 2a, the magnetic field from the exciting coil 30 is received by the first coil 11, and the generated induced current is transmitted to the second coil 12. The second coil 12 may send a position instruction signal to the tablet 2.

  DESCRIPTION OF SYMBOLS 1 ... Position indicator, 1a ... Pen tip part, 1b ... Tail part, 2 ... Tablet, 2a ... Position detection area, 2b ... Outer frame, 10 ... Position detection apparatus, 11 ... First coil, 12 ... Second Coil, 13 ... capacitor, 14 ... transmission unit, 15 ... power source extraction circuit, 16 ... timing extraction circuit, 17 ... delay circuit, 18 ... continuous signal detection circuit, 19 ... writing pressure / time conversion circuit, 20 ... counter, 21 ... P / S conversion circuit, 22 ... switch, 26 ... counter, 30 ... exciting coil, 31 ... shield plate, 32 ... liquid crystal panel, 33 ... sensor glass, 34-36 ... flexible substrate, 40 ... drive circuit, 41 ... loop coil , 42 ... selection circuit, 43 ... amplification circuit, 44 ... band pass filter, 45 ... detection circuit, 46 ... sample and hold circuit, 47 ... A / D conversion circuit, 48 ... CPU, 49 ... oscillation circuit 51 ... amplifier unit

Claims (7)

A plurality of loop coils are arranged in parallel in a predetermined direction, and include a tablet provided with an excitation coil wound around the outer periphery of the position detection region, and a substantially rod-shaped position indicator.
A position detection device for detecting a position indicated by the position indicator on the tablet by sending a signal from the excitation coil to the position indicator and detecting a signal from the position indicator by the plurality of loop coils. In
In the position indicator,
A first coil disposed at one end proximate to the position detection surface of the tablet;
A second coil spaced apart from the first coil;
A signal transmission unit that connects the first coil and the second coil, and an electrical signal that is induced in the second coil by a signal from the excitation coil is transmitted through the signal transmission unit. Transmitted to the first coil,
A position detection device, wherein a signal is sent from the first coil to the loop coil. The position detection device according to claim 1, wherein the first coil and the second coil are connected in series or in parallel. The position indicator includes a capacitor,
The position detection device according to claim 2, wherein a resonance circuit is configured by the first coil, the second coil, and the capacitor. The position detection device according to claim 1, wherein the transmission unit includes an amplification unit that amplifies an electric signal induced in the second coil.   In an electromagnetic induction type position indicator that inputs a coordinate position on a position detection surface, the position pointing unit is spaced apart from the first coil and the position detection surface upward from the first coil in a normal use state. A position indicator having a second coil provided thereon, and a signal transmission means for transmitting an electric signal induced in the second coil to the first coil.   The position indicator according to claim 5, wherein the first coil and the second coil are connected in series or in parallel to each other.   The position indicator according to claim 6, wherein a resonance circuit is configured by a synthetic coil formed by connecting the first coil and the second coil in series or in parallel with each other and a capacitor. .

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