JPH04107723A - Input device of electrostatic coupling system - Google Patents

Abstract

PURPOSE:To eliminate the need for a battery in a coordinate indicator by transmitting a signal with frequency different from that of a signal transmitted from the coordinate indicator from a tablet side to the coordinate indicator, and setting it as a power source for the coordinate indicator by receiving and rectifying by the coordinate indicator. CONSTITUTION:When the tip of the coordinate indicator 1 is abutted with a prescribed position on the tablet 2, a signal with frequency f1 transmitted from the coordinate indicator 1 is induced on an X-electrode wire 3 in the neighborhood of the position where the tip of the coordinate indicator 1 is abutted by electrostatic coupling. Also, at this time, a signal with frequency f2 different from that of the signal transmitted from the coordinate indicator 1 sent from a power transmission circuit 9 is introduced to a Y-electrode wire 4 via an X/Y change-over switch, and is transmitted to the coordinate indicator 1. The coordinate indicator 1 receives the signal with frequency f2 with a reception circuit 10, and rectifies it into DC at a rectifier circuit 11, and applies it to a transmission circuit 12 as the power source. In such a way, it is possible to eliminate the need for the battery that is the power source to drive an oscillation circuit in the coordinate indicator.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a wireless type, that is, a wireless capacitive coupling type input device, and particularly to a wireless type input device that transmits signals from a tablet without using a battery as a power source for a coordinate indicator. This transmitted signal is then used as energy.

[Prior Art] A wireless type coordinate input device using a conventional capacitive coupling method includes a tablet having electrode wires arranged at predetermined intervals in the coordinate axis direction, and a desired point on the tablet via an insulating material. A detection electrode is provided on a coordinate indicator such as an input pen or a cursor that inputs coordinates by contacting a position.

A frequency signal oscillated from an oscillation circuit within the coordinate indicator is induced in the electrode wire by electrostatic coupling between the detection electrode and the electrode wire of the tablet. This induced signal is amplified, digitally converted, and guided to calculation means consisting of a micro combinator, and this calculation means calculates the contact position of the coordinate indicator based on the magnitude of the induced signal at that time. There is.

For example, Japanese Patent Publication Nos. 52-4414 and 52-23739 are known.

[Problems to be Solved by the Invention] Since the coordinate input device described above is wireless, it requires a battery to serve as a power source for parking the oscillation circuit in the coordinate indicator, which increases the cost and the hassle of periodic battery replacement. In addition, there was a problem that a power switch was required to save power, making the structure complicated. The coordinate indicator receives a signal different from the signal, and the direct current obtained by rectifying this signal is used as a power source for the coordinate indicator.

Means for Solving the Problems] The present invention has been made in view of the above-mentioned conventional problems, and includes a coordinate indicator having an oscillation circuit, a receiving circuit, and a rectifying circuit therein, and a coordinate indicator that transmits signals from the coordinate indicator. A capacitive coupling type input device comprising a tablet that capacitively couples a signal, the input device transmitting a signal having a frequency different from the signal transmitted from the coordinate indicator from the tablet side to the coordinate indicator, and A capacitive coupling type input device characterized in that the input device receives and rectifies the signal and uses it as a power source for a coordinate indicator.

Embodiment] An embodiment of the present invention will be described with reference to the accompanying drawings. 1st
The figure is an overall block diagram of the capacitive coupling type human power device of the present invention. A detection electrode is provided at the tip of the coordinate indicator to be electrostatically coupled to an electrode wire arranged on the tablet. FIG. 2 is an explanatory diagram of the electrostatic coupling between the coordinate indicator and the electrode wires of the tablet. FIG. 3 is a tablet side electrode wire circuit diagram.

Here, the position coordinates are detected and the tablet 2 is sent to the coordinate indicator 1.
We will explain the power transfer from .

First, when detecting the X coordinate as the coordinate position detection of the tablet, the X electrode wire selection circuits @5 connected to the X electrode wires 3°3, . . . of the tablet 2 are sequentially turned on. Next, when the tip of the coordinate indicator 1 is brought into contact with a desired position on the tablet 2, the coordinate indicator 1 A frequency f signal (see FIG. 4) transmitted from the center is induced. At this time, the X/Y changeover switch 7 (see FIG. 3) is connected to the X side, and the signal is guided to the amplifier 8. Also, at this time, a signal (see FIG. 4) with a frequency f2 different from the signal transmitted from the coordinate indicator 1 sent from the power transmission circuit 9 is sent to the Y electrode lines 4, 4, . . . for X/Y switching. The signal is guided by a changeover switch valve and transmitted toward the coordinate indicator 1. Coordinate indicator 1
This signal of frequency f2 is received by a receiving circuit 10, rectified into direct current by a rectifying circuit 11, and applied as a power source to a transmitting circuit 12 by a circuit (not shown). Also, as mentioned above, when calculating the coordinate position on the X side, the Y side electrode #! When transmitting power from 4゜4 to coordinate indicator 1 and calculating the coordinate position on the Y side, turn off the power by transmitting power from electrode wire 3゜3 on the X side to coordinate indicator 1. can be supplied. It is necessary to reduce the power consumed within the coordinate indicator 1 as much as possible, and to set the power of the power transmission circuit 9 on the tablet 2 side to a certain level. Regarding the coordinate position signal, based on the signal transmitted from the coordinate indicator 1,
The signal f1 induced on the electrodes 13,3 (4,4) is amplified by the amplifier 8 and applied to the bandpass filter 13. The signal output from the bandpass filter 13 is detected by the detection circuit 14 and then passed through the analog-to-digital converter 15 (
The signal is applied to the arithmetic circuit 16 via an A/D converter (hereinafter referred to as an A/D converter). The control circuit 17 controls the operations of the X electrode line selection circuit 3, the Y electrode line selection circuit 4, the A/D converter 15, and the arithmetic circuit 16.

Incidentally, by setting the frequency f and the frequency f2 to sufficiently different frequencies to prevent beats from occurring, electric power can be efficiently supplied. Furthermore, in this embodiment, the X and Y electrode wires are switched for power transmission, but the present invention is not limited to this, and a dedicated electrode wire for power transmission is provided on the bottom surface of the X and Y electrode wires. Of course, it is also possible to arrange .

[Effects of the Invention] Since the present invention has the above configuration, it does not require a battery in the coordinate indicator, so it has advantages such as cost, troublesome battery replacement, and no need for a power switch. .

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and Fig. 1 is an overall block diagram, Fig. 2 is an explanatory diagram of electrostatic coupling, Fig. 3 is a tablet side electrode wire circuit diagram, and Fig. 4 is a schematic diagram of power reception. be. 1... Coordinate indicator, 2... Tablet, 3.4... Electrode line, 5, 6... Electrode line selection circuit 9... Electric power transmitting circuit, 10...receiving circuit, 11... rectifying circuit, 12... transmitting circuit, 18... oscillating circuit,

Claims (1)

[Claims] A capacitive coupling type input device comprising a coordinate indicator having an oscillation circuit, a receiving circuit, and a rectifying circuit therein, and a tablet that capacitively couples a signal transmitted from the coordinate indicator, A capacitive coupling type input device characterized in that a signal having a frequency different from that of the transmitted signal is transmitted from the tablet side to the coordinate indicator, received and rectified by the coordinate indicator, and used as a power source for the coordinate indicator. .