JPH05113844A - Cordless digitizer - Google Patents

Abstract

PURPOSE:To supply electric power to a cursor part by electrostatic coupling as to the cordless digitizer which consists of the cursor part and a tablet part and transmit signals between those parts by radio. CONSTITUTION:The tablet part 10 of this digitizer is constituted by providing an electrostatic electrode 11 on a power supply grid plate for supplying the electric power to the cursor part 20 and an alternating voltage of specific frequency is applied from a power source 12 to this electrostatic electrode 11. Consequently, an electrostatic voltage is induced at a power receiving electrode 21 provided in the cursor part 20 and the induced voltage is rectified and smoothed by a circuit consisting of diodes D1 and D2 and a capacitor C1 and supplied to respective parts in the cursor part 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cordless digitizer which is composed of a tablet unit and a cursor unit and which does not require a cable when transmitting signals between them and supplying power from the tablet unit to the cursor unit. ..

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 7, a cordless digitizer of this type has a tablet portion 10 and a cursor portion 20, and a plurality of grid plates 10a to 10d are stacked in the tablet portion 10. Has been done. That is, power supply grid plates 10a and 10b having winding coils for supplying power to the cursor unit 20 by electromagnetic coupling are arranged in the upper layer of the tablet unit 10, and the cursor unit is in the lower layer thereof. Position detection grid plates 10c and 10d having a plurality of winding coils for performing position detection and the like of 20 by electromagnetic coupling are arranged.

Next, FIG. 8 is a block diagram of the power supply of such a cordless digitizer.
The power supply from the cursor unit 20 to the cursor unit 20 is performed by the electromagnetic coupling as described above. That is, when an alternating voltage of a predetermined frequency is applied from the power supply 19 to the coil-shaped conductor L5 formed on the power supply grid plates 10a and 10b in the tablet unit 10, the cursor unit 20 placed on the power supply grid plate is applied. A voltage is induced in the power receiving coil L6 inside. This induced voltage is applied to the capacitors C5 to C7 and the diode D.
DC voltage V is rectified and smoothed by a circuit composed of 1 and D2.
This is given to the oscillation circuit 23 as _{CC, and} as a result, the cursor coil L3 for detecting the position of the cursor unit 20 oscillates, and an oscillating current flows through the coil L3.

FIG. 9A shows a first example of power supply by such an electromagnetic coupling system, which has already been proposed by the present applicant (Japanese Patent Application No. 3-136972).
issue). This is because a conductor pattern (winding) L5 is provided on the power grid plates 10a and 10b (the grid plate 10b is not shown in FIG. 9) and the longitudinal direction thereof is inclined by 45 degrees in both the X-axis direction and the Y-axis direction. Respectively to have
An alternating voltage of a predetermined frequency is applied from the power source 19a to the formed conductor pattern L5 on the grid plate 10a, and the conductor pattern L5 on the grid plate 10b is 90 degrees out of phase with the power source 19a. An alternating voltage is applied from the power supply 19b. As a result, in the power receiving coil L6,
The voltage is induced and the cursor coil L3 arranged concentrically or coaxially with the power receiving coil L6 oscillates. When the cursor coil L3 oscillates, the power grid plate 10
Position detection grid plate 1 laminated under a and 10b
The position of the cursor portion 10 is detected by 0c and 10d. That is, as shown in FIG. 9B, the grid plate 10c
A plurality of windings L4 are formed parallel to the X-axis direction, and a plurality of windings L4 are formed parallel to the Y-axis direction on a grid plate 10d (not shown), which is generated from the cursor coil L3. The generated magnetic field is induced as a voltage in these X-axis and Y-axis winding coils L4. The induced voltage is detected by sequential scanning of the winding coil L4 for the X axis and the Y axis, and the XY plane position of the cursor unit 20 is calculated from the detected coordinates of the X axis and the Y axis. ..

FIG. 10 is a diagram showing a second example of power supply by electromagnetic coupling in the same manner.
0a and 10b are omitted, and each winding L5 is commonly used for power supply and signal detection. That is, the position detecting grid plates 10c and 10d (the grid plate 10d is not shown in FIG. 10) are configured as described above, and the position detecting grid plate 10c is used for detecting the position of the cursor portion 20. When the position detecting grid plate 10d is used for supplying power to the cursor portion 20 while the position detecting grid plate 10c is used for supplying power, the position detecting grid plate 10d is used for position detection. It is intended to be used for.

[0006]

In the case of power supply by such a power supply coupling method, the magnetic field generated becomes uneven because the conductor pattern of the power supply grid plate becomes larger as the tablet portion becomes larger, Particularly in the case of the first example, the voltage induced in the power receiving coil fluctuates depending on the position where the cursor is placed, and stable power is not supplied to the cursor coil, while the current is constantly supplied to the winding coil. Since it is continuously driven and driven, there is a defect that unnecessary radiation becomes large. Therefore, a method of dividing the conductor pattern and driving each of the conductor patterns can be considered, but this method increases the cost. In addition, in the case of the second example, the fluctuation of the induced voltage due to the position where the cursor portion is placed is small, but since the position of the power receiving coil and the cursor coil are not coaxially arranged, The winding coil to be selected is different when the power is supplied and when the position of the cursor is detected, and the winding selection control becomes complicated. Further, if the power receiving coil and the cursor coil are arranged coaxially in order to eliminate such a defect, there is a drawback that the magnetic field on the power receiving coil side and the magnetic field on the cursor coil side interfere with each other and the receiving sensitivity of the cursor coil is lowered. It was

[0007]

In order to solve such a problem, the present invention applies the alternating voltage to the second electrode provided in the tablet part to the first electrode provided in the cursor part. The induced voltage is generated. Further, the second grid electrode is provided on the third grid plate to supply power to the cursor portion, and the plane coordinate position of the cursor portion is detected by electromagnetic coupling through the first and second grid plates.

[0008]

The power supply from the tablet unit to the cursor unit is performed by electrostatic coupling. Power is supplied to the cursor unit by electrostatic coupling via the third grid plate, and the position of the cursor unit is detected by electromagnetic coupling via the first and second grid plates.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a cordless digitizer according to the present invention. In the tablet unit 10 of this digitizer, an electrostatic electrode 11 is formed over the entire surface on a power grid plate 10a for supplying power to the cursor unit 20, and a power receiving electrode is provided in the cursor unit 20. By applying an alternating voltage of a predetermined frequency from the power source 12 to 11, an electrostatic voltage is induced in the power receiving electrode 21, and this induced voltage is further applied to the diode D.
The power is supplied to each part in the cursor unit 20 via a rectifying / smoothing circuit composed of 1, D2 and a capacitor C1. When power is supplied to the cursor unit 20 in this way, the cursor coil L3 oscillates as in the conventional case, and the position of the cursor unit 20 is detected by the position detection grid plates 10c and 10d stacked below the power supply grid plate 10a. To be done. In this case, the power supply grid plate 10b which has been conventionally used is omitted.

FIGS. 2 and 3 show modified examples in the case of power supply by electrostatic coupling. In both cases, the electrostatic voltage induced in the power receiving electrode 21 of the cursor section 20 is efficiently moved by the cursor. Power receiving electrode 2 so that it can be transmitted to each part in the part
The resonance circuit 22 is arranged after 1. Providing such a resonance circuit 22 is particularly effective when the load current in the cursor portion is small. As in the example shown in FIG. 3, the induced electrostatic voltage may be applied to the battery E so that the battery E can be used while being constantly charged.

By such electrostatic coupling, the cursor portion 20
When the power is supplied to the side, unnecessary radiation is reduced as compared with the case of the power supply by the conventional electromagnetic coupling method, and the induced voltage of the cursor portion 20 is reduced no matter where it is placed on the tablet portion 10. Less variability. That is, in the case of electrostatic coupling, even if an alternating voltage is constantly applied to all the electrostatic electrodes 11, only the electrostatic electrodes corresponding to the position of the power receiving electrode 21 of the cursor portion 20 will flow current, and thus the winding will always be performed. The unnecessary radiation can be reduced as compared with the case of electromagnetic coupling in which a current is passed through the wire coil, and the power supply grid plate 10 of the tablet unit 10 can be reduced.
By preparing a pattern of the power receiving electrode 21 such that the coupling with the electrostatic electrode 11 is tight regardless of the position of the cursor portion 20 placed on a, the voltage induced in the power receiving electrode 21 is electromagnetically induced. It is more stable than the mold. Further, power can be supplied to the cursor unit 20 by only one power supply grid plate 10a, and the cost of the device can be reduced.

Next, the following figure shows a detailed example of power supply by such electrostatic coupling, and FIG.
It is a figure which shows an example of the pattern of the above-mentioned electrostatic electrode 11 and the power receiving electrode 21. That is, FIG. 4A shows the electrostatic electrode 1 formed on the power supply grid plate 10a in the tablet part.
1 shows a pattern of No. 1 and 11 ₁ and 11 ₂ are electrostatic electrodes having polarities different from each other. 4B shows a pattern of the power receiving electrodes 21 formed on the cursor portion 20, and 21 ₁ and 21 ₂ are power receiving electrodes having polarities different from each other. Here, the distance between the electrostatic electrodes 11 ₁ and 11 ₂ is L,
The areas of the power receiving electrodes 21 ₁ and 21 ₂ are S2, S1, and
When the diameter of the power receiving electrode 21 is D, it is desirable to form a pattern of the electrode 21 such that S1≈S2 (1) D≈nL (n is a positive integer, n> 2) (2).

5A to 5C are various pattern diagrams of the power receiving electrode 21, and the electrostatic coupling is dense regardless of the orientation of the power receiving electrode 21 placed on the pattern of the electrostatic electrode 11. Shows a different pattern. Here, it is desirable that the electrodes are formed so that L = 1 (1 is the distance between the electrodes 21 ₁ and 21 ₂ ).
The electrostatic coupling with 1 becomes tight coupling, and the power transfer efficiency is improved.

If the power receiving electrode 21 is formed of a power receiving body other than metal by using, for example, a conductive plastic or thinning a conductive paint, power is supplied to the cursor portion 20 by electrostatic coupling. Even if the power receiving electrode 21 for detecting the position and the cursor coil L3 for detecting the position of the cursor portion 20 by electromagnetic coupling are arranged coaxially, signals generated between them do not interfere with each other. Also,
Since power can be supplied by electrostatic coupling via the power grid plate 10a, a paper suction plate for electrostatically adsorbing the paper placed and placed between the power grid plate 10a and the cursor unit 20 A sheet suction plate can be used in common with the grid plate 10a, and a sheet suction plate is separately provided for the gap between the electrostatic electrode 11 of the power grid plate 10a and the power receiving electrode 21 of the tablet unit 20. The power transmission efficiency can be improved as compared with the above.

Next, FIG. 6 shows an example in which power is supplied to the cursor section 20 by electrostatic coupling and the supplied power voltage is directly applied to the cursor coil L3 without being rectified.
(A) of the same figure is a front view showing the positional relationship between the electrostatic electrode 11 and the power receiving electrode 21, and (b) of the same figure is a diagram showing its operating principle. That is, as shown in FIG.
When an alternating voltage signal of a predetermined frequency is applied to the electrostatic electrode 11 on the power supply grid plate 10a from this, this voltage signal is resonated by the capacitor C4 and the cursor coil L3 via the power receiving electrode 21 in the cursor portion 20. Applied directly to the circuit. Then, this resonance circuit is driven into an oscillating state, and a magnetic field is generated from the cursor coil L3. The generated magnetic field is induced as a voltage signal in the X-axis and Y-axis winding coil L4 of the position detection grid plates 10c and 10d stacked below the power supply grid plate 10a. The position of the cursor unit 20 is calculated by sequentially scanning the Y-axis winding coil L4 and detecting the induced voltage signal.

As described above, power is supplied to the cursor section 20 by electrostatic coupling through the power source grid board 10a, and the position of the cursor section 20 is determined by the position detecting grid board 10a.
The detection is performed by electromagnetic coupling through c and 10d. As a result, even if the power receiving electrode 21 and the cursor coil 3 are arranged coaxially, the signals generated between them do not interfere with each other.

[0017]

As described above, according to the present invention, since power is supplied from the tablet portion to the cursor portion by electrostatic coupling, unnecessary radiation can be suppressed and the power source does not fluctuate with respect to the cursor portion. Can be supplied. In addition, the power to the cursor is supplied by electrostatic coupling, and the position of the cursor is detected by electromagnetic coupling.Therefore, the electrode for receiving power and the coil for position detection are coaxially arranged in the cursor. However, mutual interference of signals does not occur between them.

[Brief description of drawings]

FIG. 1 is a block diagram of power supply showing an embodiment of a cordless digitizer according to the present invention.

FIG. 2 is a block diagram of power supply showing a modification of the above embodiment.

FIG. 3 is a block diagram of power supply showing a modification of the above embodiment.

FIG. 4 is a supply side when power is supplied by electrostatic coupling,
It is an electrode pattern diagram of the power receiving side.

FIG. 5 is an electrode pattern diagram on the power receiving side when power is supplied by electrostatic coupling.

FIG. 6 is a diagram showing another embodiment of the cordless digitizer.

FIG. 7 is a diagram showing an arrangement state of each unit of a conventional cordless digitizer.

FIG. 8 is a block diagram of a cursor unit of a conventional cordless digitizer.

FIG. 9 is a configuration diagram of a conventional cordless digitizer.

FIG. 10 is a configuration diagram of a conventional cordless digitizer.

[Explanation of symbols]

 10 tablet part 10a power supply grid plate 10c, 10d position detection grid plate 11 electrostatic electrode 12 power supply 20 cursor part 21 power receiving electrode 22 resonance circuit L3 cursor coil L4 winding coil

Front page continuation (72) Inventor Konobu Sakurada 503-10 Shinanomachi, Totsuka-ku, Yokohama, Kanagawa Prefecture Graphtec Co., Ltd.

Claims (2)

[Claims] 1. A cordless digitizer comprising a cursor unit and a tablet unit for detecting a position where the cursor unit is placed, and wirelessly transmitting signals between these units and supplying power from the tablet unit to the cursor unit. In the above, the cursor part is provided with a first electrode, the tablet part is provided with a second electrode, and an alternating voltage is applied to the second electrode to induce a voltage in the first electrode. A cordless digitizer characterized in that power is supplied to the cursor portion. 2. The first and second grid plates and the cursor part, each of which comprises a cursor part and a tablet part for detecting a position where the cursor part is placed, and which detects the position of the cursor part by electromagnetic coupling. Third to supply power
A cordless digitizer including the grid plate in the tablet unit, the cursor unit including a first electrode, and
The grid plate is provided with a second electrode, and an alternating voltage is applied to the second electrode to induce a voltage in the first electrode to supply power to the cursor portion, and at the same time A cordless digitizer characterized in that the position of the cursor portion is detected by the grid plate of 2.