JPH10171584A - Coordinate input device for computer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coordinate input device with less power consumption by lighting a light emitting element between a current source and a loop coil by a current made to flow from the current source to the loop coil. SOLUTION: The current generated in the current source 1 is passed through the light emitting element 3, passed through a transmission/reception switching circuit 6 and made to flow to the loop coil 5 selected by a coil switching circuit 7 and an alternate magnetic field is radiated. In this case, since the light emitting element 3 is made to emit light by the current required for generating the alternate magnetic field in the loop coil 5, another special power source is not required. For instance, in the case of using a light emitting diode as the light emitting element 3, the current of about 10mA is required, and in this case, since the light is emitted by the current made to flow to the loop coil 5 originally required for achieving a function as this coordinate input device without the need of a special power source, the current of about 10mA, that is the power consumption, is saved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate input device which is one of input devices of a computer, and more particularly to a light emitting element used for determining whether the power of the coordinate input device is ON or OFF.

[0002]

2. Description of the Related Art Conventionally, various types of position detection methods in coordinate input devices have been known.

[0003] The present invention is based on the electromagnetic transfer method among them, and FIG. 4 is a schematic configuration diagram for explaining the basic operation.

[0004] One conventional example will now be described with reference to FIG.

In FIG. 1, reference numeral 5 denotes a loop coil disposed on a printed circuit board, and reference numeral 8 denotes a position indicator which includes at least one coil and a capacitor and includes a tuning circuit for setting a predetermined frequency to a tuning frequency. 3 is a light emitting element,
A component that emits light when a current flows is used, and usually a light emitting diode or the like is used. Reference numeral 4 denotes a power supply, which usually uses a circuit for rectifying and smoothing a battery or an AC power supply, and is not necessary when a DC current is supplied from the outside. 6 is a switching circuit for switching between reception and transmission, and 7 is a switching circuit for switching a plurality of loop coils. 2
Is a receiving circuit including a high-frequency amplifier, a detector, an A / D converter, a signal processing unit, and the like.

Reference numeral 1 denotes a current source for generating an alternating current flowing through the loop coil, and is constituted by an oscillation circuit, an amplification circuit, and the like. The current output from the current source 1 flows through the transmission / reception switch 6 and the loop coil switch 7 to the loop coil 5. Then, an electromagnetic wave is generated from the loop coil 5, and a resonance circuit or the like in the position indicator 8 resonates by the electromagnetic wave. When the transmission / reception switch 6 is switched to the reception circuit 2 after a predetermined period, a response electromagnetic wave is generated from the position indicator 8. This response electromagnetic wave is received by the loop coil 5,
The received signal is passed to the receiving circuit 2. The receiving circuit 2 performs a predetermined arithmetic processing based on the digital information obtained from each of the loop coils 5, and obtains X on the tablet of the position indicator.
Calculate coordinates and Y coordinates.

Conventionally, for example, a light emitting diode was directly connected to the power supply to emit light so that the ON / OFF of the power supply and the state of the coordinate input device could be recognized at a glance. Because it requires current,
There is a disadvantage that power consumption increases accordingly. Also, the current that can be used is limited, which has been a barrier to the performance improvement of the coordinate input device.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a coordinate input device that consumes less power.

[0009]

In order to achieve the above object, a coordinate input device according to the present invention employs a structure in which a light emitting element is turned on by a current flowing from a current source to a loop coil.

[0010]

According to this structure, the current used only for light emission of the light emitting element is eliminated, and the light emitting element can be turned on without increasing power consumption. Therefore, a low power consumption coordinate input device is provided. .

[0011]

Next, embodiments of the present invention will be described.

Embodiment 1 FIG. 1 shows a first embodiment of the present invention. The difference from the conventional example of FIG. 4 is that the light emitting element 3 is added between the current source 1 and the transmission / reception switching circuit 6. In FIG. 1, a current generated by a current source 1 passes through a light emitting element 3, passes through a transmission / reception switching circuit 6, flows into a loop coil 5 selected by a coil switching circuit 7, and emits an alternating magnetic field. At this time, the light emitting element 3 emits light. In this case, since the light emitting element 3 emits light with a current necessary for generating an alternating magnetic field in the loop coil 5, no special power supply is required. For example, when a light emitting diode is used as the light emitting element 3, about 10
Although a current of about mA is required, this embodiment does not require a special power supply and emits light by a current flowing through the loop coil 5 which is originally required to function as a coordinate input device. That is, power consumption can be reduced.

<Embodiment 2> Next, a second embodiment will be described with reference to FIG. FIG. 2 is an extension of the embodiment of FIG. 1 and differs from FIG. 1 in that there are a plurality of light emitting elements 3 and a selection means for selecting one or some of the light emitting elements 3. 9 was added. This selecting means can be realized by using, for example, an analog switch. In this embodiment, an analog switch is used as the selecting means 9 and ON / OFF of the switch is controlled by a control signal from the CPU.

In FIG. 2, the current generated by the current source 1 passes through one or several of the plurality of light emitting elements 3 by the selection means 9 and flows into the loop coil 5 selected by the coil switching circuit 7. Emit alternating magnetic fields. At this time, the light emitting element 3 emits light. Also in this case, as in the first embodiment, no special power supply is required, and the light is emitted by the current flowing through the loop coil 5 which is originally required to function as the coordinate input device.
That is, power consumption can be reduced.

<Embodiment 3> FIG. 3 is an extension of the embodiment of FIG. What is different in comparison with FIG.
There are a plurality of current sources 1, a means 10 for controlling an output current from the current source 1 corresponds to each of the plurality of current sources 1, and a plurality of light emitting elements 3 corresponding to each of the control means 10. That is. In the present embodiment, a three-state buffer is used as the control means 10, and control of the control means is performed using a control signal generated from the CPU.

In FIG. 3, the current generated by the current source 1 flows to the corresponding control means 10. Next, CPU
When one or several of the control means 10 are selected by the signal from the control unit 10, the current passes through one or some of the plurality of light emitting elements 3, and the current passes through the loop coil 5 selected by the coil switching circuit 7. It flows in and emits an alternating magnetic field. At this time, the light emitting element 3 emits light. Also in this case, a special power supply is not required as in the first embodiment, and light is emitted by the current flowing through the loop coil 5 which is originally required to fulfill the function as a coordinate input device, so that power consumption can be reduced.

<Expansion> In the above embodiments, the light emitting diode is used as the light emitting element. However, the present invention can be applied to the case where another light emitting element is used. Further, although a multiplexer is used as the coil switching circuit, the present invention can be similarly applied to other methods.

Furthermore, in the second embodiment, the analog switch is used as the light emitting element selection means. However, the present invention can be similarly applied to other methods such as a three-state buffer instead of the switch. .

In the second and third embodiments, the control signal from the CPU is used as the control signal.
The method is not limited to U, and other methods can be applied to the present invention.

[0020]

According to the present invention, it is possible to easily realize a low power consumption coordinate input device by using a configuration in which a light emitting element is turned on by a current flowing from a current source to a loop coil.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a coordinate input device according to the present invention.

FIG. 2 is a schematic configuration diagram of an embodiment of a coordinate input device according to the present invention.

FIG. 3 is a schematic configuration diagram of an embodiment of a coordinate input device according to the present invention.

FIG. 4 is a schematic configuration diagram of a coordinate input device according to the related art.

[Explanation of symbols]

 1: Current source 2: Receiving circuit 3: Light emitting element 4: Power supply 5: Loop coil 6: Transmission / reception switching circuit 7: Loop coil switching circuit 8: Position indicator including tuning circuit 9: Light emitting element selection means 10: Output current Control means to control

[Procedure amendment]

[Submission date] September 19, 1997

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

FIG. 4

Claims (3)

[Claims] 1. A coordinate input device for a computer using an electromagnetic induction effect, wherein a loop coil for emitting an alternating magnetic field or a loop coil for emitting and receiving an alternating magnetic field, and a transmission current is supplied to the loop coil. A light emitting element is provided between the current source and the loop coil, and the light emitting element emits light by a current flowing from the current source to the loop coil. Coordinate input device. 2. The coordinate input device for a computer according to claim 1, wherein a plurality of light emitting elements are provided for one current source, and the plurality of light emitting elements are provided between the current source and the plurality of light emitting elements. A coordinate input device for a computer, comprising: selection means for selecting one or some of the light-emitting elements, wherein a light-emitting element through which current flows is arbitrarily selected by the selection means. 3. The coordinate input device for a computer according to claim 1, further comprising: a plurality of current sources provided with a means for controlling an output current; and a light emitting element corresponding to each of the plurality of current sources.
A current flowing through the loop coil by controlling the currents of the plurality of current sources, and one or several of the plurality of light emitting elements are arbitrarily selected to emit light. Input device.