JPH05274080A - Coordinate detector - Google Patents

Abstract

PURPOSE:To reduce current consumption by cutting off conduction on a panel, a driving circuit, an instruction device, and a coordinate detection circuit completely by stitching a conduction switching means to an off-state when the standby state of coordinate detection continues for prescribed time. CONSTITUTION:When a state where a stylus pen 13 is separated from a coordinate detection panel 11 continues for the prescribed time and a sleep command to attain low power consumption is issued from a host, a control circuit 17 outputs a SLEEP signal to a conduction control signal generation circuit 19. The output of the conduction control signal generation circuit 19 goes to level, and a conduction ON/OFF circuit 18 is turned off, which stops the conduction on the coordinate detection panel 11, the driving circuit 12, a signal detection circuit 14, a signal processing circuit 16, and the control circuit 17. Also, the conduction ON/OFF circuit 18, the conduction control signal generation circuit 19, a status signal generation circuit 20, and furthermore, a switch circuit 15 are always energized, however, the power consumption in those circuits are low, therefore, the current consumption can be remarkably reduced compared with a conventional device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate detecting device used for inputting characters and figures into a computer.

[0002]

2. Description of the Related Art In recent years, an integrated display input device has been developed in which a transparent tablet, which is a coordinate detection device, is placed on a display screen such as a liquid crystal display so that display and input can be performed on the same plane. There is. This integrated display / input device can directly indicate an object or the like displayed through a tablet with a stylus pen, which is an instruction device, and can input characters or figures by handwriting and display them at that position. It has excellent operability.

FIG. 4 is a block diagram showing the configuration of a coordinate detecting device in such an integrated display / input device.

In FIG. 1, reference numeral 1 is a coordinate detection panel having a plurality of transparent scanning lines arranged in the X / Y directions, and reference numeral 2 is a drive circuit for driving each scanning line of the coordinate detection panel 1. Reference numeral 3 is a stylus pen for designating an arbitrary position on the coordinate detection panel 1. As shown in FIG. 5, the stylus pen 3 is pressed by the signal detection circuit 4 that detects a signal induced between the pen tip and the scanning line of the coordinate detection panel 1, and the pen tip of the stylus pen 3. The switch circuit 5 for detecting whether or not it is built is built in. Further, 6 is a signal processing circuit that obtains a signal useful for coordinate detection by performing amplification, filtering, comparison processing with a reference voltage, etc., of the signal output from the signal detection circuit 4 in the stylus pen 3, and 7 is each of the above configurations Coordinate detection panel 1 instructed by the stylus pen 3 based on the signal output from the signal processing circuit 6 while performing overall control of the unit and interface control with the host.
It is a control circuit that calculates the coordinate values above.

Next, the operation of this coordinate detecting device will be described.

First, when the control circuit 7 receives a coordinate measurement start command from the host, it outputs a signal (data, clock, etc.) for driving the scanning line to the drive circuit 2. Drive circuit 2
When this signal is received, scans each scanning line arranged on the coordinate detection panel 1 sequentially from one end in each of the X / Y directions (applying a predetermined voltage). At this time,
When the stylus pen 3 has a pen tip near the scanning line being scanned, the signal detection circuit 4 inside the stylus pen 3 detects a signal induced between the pen tip and the scanning line. Here, the level of the detection signal increases as the distance between the scanning line during voltage application and the pen tip decreases, and reaches the maximum at the point closest to the pen tip. The signal detected by the signal detection circuit 4 is input to the signal processing circuit 6, where it is amplified and filtered, then compared with a reference voltage, and a signal indicating the comparison result is sent to the control circuit 7. Is output. When the control circuit 7 receives the signal that the detection signal exceeds the reference voltage, the control circuit 7 measures the time from the start of scanning in each of the X / Y directions of the scanning line to the coordinates designated by the stylus pen 3 based on the measured value. The coordinate value on the detection panel 1 is calculated.

This coordinate measurement is performed every time a coordinate measurement command is received from the host, and when the coordinate measurement is completed, the control circuit 7 outputs an interrupt signal to the host. The host receives the interrupt signal and takes in coordinate data.

On the other hand, the switch circuit 5 in the stylus pen 3 detects whether or not the pen tip of the stylus pen 3 is pressed, and turns on the switch signal when the pen tip is pressed. At that time, even if the stylus pen 3 is not actually present on the coordinate detection panel 1, the switch signal will be turned ON if the pen tip is pressed. Therefore, the control circuit 7 determines the true value based on the measured coordinate value at that time. Judge false and notify the host of the result. Here, when the state in which the coordinate data cannot be measured (the stylus pen 3 is away from the coordinate detection panel 1) continues for a predetermined time, the host judges that the coordinate detection device is not used and the sampling rate (1 Decrease the number of coordinate measurement commands generated per second). Thereby, the power consumption of the coordinate detecting device is reduced.

Recently, a coordinate detection device with an autosampling function that automatically detects coordinates regardless of a command from the host is used, and the autosampling function of the coordinate detection device is used according to the load condition of the host. ON / O
A method of switching the FF is also often adopted.

By the way, according to such a method of reducing the power consumption, although it is possible to achieve the reduction of the power consumption, a certain amount of the power is always consumed, and it is not possible to expect a dramatic reduction in the power consumption. ..

As another method of reducing power consumption, a method of stopping the operation of the entire coordinate detecting device by a command from the host can be considered. However, with this method, it is necessary to check the start of use by the user by operating the coordinate detection panel at regular intervals. Therefore, reduction of power consumption in the true sense cannot be expected.

[0012]

SUMMARY OF THE INVENTION The present invention is intended to solve such problems, and an object of the present invention is to provide a coordinate detecting apparatus capable of significantly reducing power consumption during standby for coordinate measurement.

[0013]

In order to achieve the above-mentioned object, a coordinate detecting device of the present invention has a panel having a plurality of scanning lines, a drive circuit for driving each scanning line of the panel, and a panel on the panel. A pen-shaped pointing device that points to an arbitrary position, a coordinate detection circuit that detects the coordinates on the panel pointed by the pointing device, and a detection unit that detects that the pen tip of the pointing device is pressed. , The panel, the drive circuit, the indicating device, and the energization switching means for switching the energization to the coordinate detection circuit ON / OFF, and the energization switching means O when the standby state for coordinate detection continues for a predetermined time.
A switching control means is provided for switching to FF and for switching the energization switching means to ON when the detection means detects that the pen tip of the pointing device is pressed.

[0014]

In the present invention, the energization switching means can switch ON / OFF of energization of the panel, the drive circuit, the pointing device, and the coordinate detection circuit. Then, when the standby state for coordinate detection continues for a predetermined time, the switching control unit switches the energization switching unit to OFF. After that, when the detection means detects that the pen tip of the pointing device is pushed, the switching control means switches the energization switching means to ON. As a result, the power consumption during standby for coordinate measurement can be significantly reduced.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the arrangement of a coordinate detecting apparatus according to an embodiment of the present invention. In the figure, 11
Is a coordinate detection panel having a plurality of transparent scanning lines arranged in the X / Y directions, and 12 is a drive circuit for driving each scanning line of the coordinate detection panel 11. Further, 13 is a coordinate detection panel 11
It is a stylus pen for designating an arbitrary position above. As shown in FIG. 2, the stylus pen 13
A signal detection circuit 14 for detecting a signal induced between the pen tip and the scanning line of the coordinate detection panel 11 and a switch circuit 15 for detecting whether or not the pen tip of the stylus pen 13 is pressed are built in. .. Reference numeral 16 is a signal processing circuit that obtains a signal useful for coordinate detection by performing amplification, filtering, comparison processing with a reference voltage, etc., of the signal output from the signal detection circuit 14 of the stylus pen 13, and 17 is a component of the above-mentioned components. The coordinate detection panel 11 which is controlled by the stylus pen 13 on the basis of the signal output from the signal processing circuit 16 while performing overall control and interface control with the host.
It is a control circuit that calculates the coordinate values above. Further, reference numeral 18 indicates ON / OFF of power supply to these coordinate detection panel 11, drive circuit 12, signal detection circuit 14, signal processing circuit 16 and control circuit 17 (hereinafter, these are referred to as power supply switching target circuits).
An energization ON / OFF switching circuit as an energization switching means for switching the energization switching means, an energization control signal generation circuit 19 for generating a signal for controlling switching of the energization ON / OFF switching circuit 18,
Reference numeral 0 is a status signal generation circuit that generates a status signal indicating the mode state up to that point (a normal mode in which the host intervenes and an auto sampling mode in which the host does not intervene).

FIG. 3 shows the energization ON / OFF circuit 1 described above.
8 is a circuit diagram showing details of an energization control signal generation circuit 19 and a status signal generation circuit 20. FIG.

As shown in the figure, the energization ON / OFF circuit 18 is composed of three resistors R1, R2 and R3 and two transistors Q1 and Q2. The energization control signal generation circuit 19 is composed of a D-flip-flop 191 and an AND gate 192. Further, the status signal generation circuit 20 comprises a D-flip flop 201. Then, these energization ON / OFF circuit 18, energization control signal generation circuit 19 and status signal generation circuit 2
0 is always energized after the system starts up. Next, the operation of the coordinate detecting device of this embodiment will be described.

In this apparatus, a normal mode in which the coordinate detection apparatus executes coordinate measurement in response to a command from the host,
It is possible to switch between an autosampling mode in which the coordinate detection device itself performs coordinate measurements without host intervention.

First, the case where the normal mode is set will be described. Note that the operation of the normal coordinate measurement is the same as the conventional one, and is therefore omitted here.

The D-flip-flop 191 in the energization control signal generation circuit 19 receives the RESE signal from the host when the power is turned on.
It is initialized by the T # signal, and its output NQ (energization control signal) is at the H level. As a result, the transistors Q1 and Q2 in the energization ON / OFF circuit 18 are turned on, and the energization switching target circuit is energized.

When the coordinate data cannot be measured (the stylus pen 13 is away from the coordinate detection panel 11) for a predetermined time, the host outputs a sleep command for reducing power consumption. , The control circuit 17 sends the energization control signal generation circuit 19 a SLEEP signal (H
Output). Then, the output NQ of the D-flip-flop 191 in the energization control signal generation circuit 19 becomes L level, the transistors Q1 and Q2 in the energization ON / OFF circuit 18 are turned off, and the energization to the energization switching target circuit is stopped. To do.

Further, the control circuit 17 generates the SLEEP signal and, at the same time, the MODE signal and the SWRITE signal (H
Active). Here, the MODE signal is at L level except in the auto sampling mode. As a result, the output Q (STATUS signal) of the D-flip-flop 201 in the status signal generation circuit 20 becomes the same L level as the MODE signal and is sent to the control circuit 17.

In this state, when the pen tip of the stylus pen 13 is pressed, the switch circuit 15 outputs the SW # signal (L active) to the energization control signal generation circuit 19.
Then, the D-flip-flop 191 in the energization control signal generation circuit 19 is reset and the output NQ becomes H level. As a result, the transistors Q1 and Q2 in the energization ON / OFF circuit 18 are turned on, and the energization of the energization switching target circuit is started again. However, at this time STATUS
Since the S signal is at the L level indicating the normal mode, the control circuit 17 waits for a command from the host even when the power supply is restarted, and starts the next operation as soon as the command from the host is received.

Next, a case where the auto sampling mode is set will be described.

In this case, if the state in which the coordinate data cannot be measured continues for a predetermined time, the control circuit 17 automatically causes SLE.
An EP signal is generated to stop the energization of the energization switching target circuit. At this time, the control circuit 17 outputs the MODE signal and the SWRITE signal as before, but the MODE signal becomes the H level in the auto sampling mode. As a result, the output Q (STATUS signal) of the D-flip-flop 201 in the status signal generation circuit 20 becomes H level.

After that, when the tip of the stylus pen 13 is pushed, the switch circuit 15 restarts the power supply to the power supply switching target circuit by the SW # signal output to the power supply control signal generation circuit 19. At this time, since the STATUS signal is at the H level indicating the auto sampling mode,
The control circuit 20 immediately starts coordinate measurement.

Thus, according to the coordinate detecting apparatus of this embodiment, the power supply to the coordinate detecting panel 11, the drive circuit 12, the signal detecting circuit 14, the signal processing circuit 16 and the control circuit 17 is stopped in the standby state of the coordinate measurement. Therefore, power consumption can be significantly reduced.

The energization ON / OFF circuit 18, the energization control signal generation circuit 19, the status signal generation circuit 20, and the switch circuit 15 are always energized.
The power consumption of these is about 100 μA, which is considerably lower than the standby power consumption (about 15 mA) of the conventional coordinate detecting device.

Although the electrostatic induction type coordinate detecting device has been described in the present embodiment, the present invention is not limited to this type. In the present embodiment, the D-flip-flop is used for the energization control signal generation circuit 19 and the status signal generation circuit 20, but a non-volatile memory or the like may be used.

[0031]

As described above, according to the coordinate detecting device of the present invention, when the standby state for coordinate detection continues for a predetermined time, the energization switching means is turned off to switch the panel, the drive circuit, the indicating device, and Since power supply to the coordinate detection circuit can be completely cut off, power consumption during standby for coordinate measurement can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining a configuration of a coordinate detection device according to an embodiment of the present invention.

FIG. 2 is a block diagram for explaining a circuit configuration inside the stylus pen of FIG.

3 is a circuit diagram showing details of an energization ON / OFF circuit, an energization control signal generation circuit, and a status signal generation circuit of FIG.

FIG. 4 is a block diagram for explaining the configuration of a conventional coordinate detection device.

5 is a block diagram for explaining a circuit configuration inside the stylus pen of FIG. 4. FIG.

[Explanation of symbols]

 11 ... Coordinate detection panel 12 ... Drive circuit 13 ... Stylus pen 14 ... Signal detection circuit 15 ... Switch circuit 16 ... Signal processing circuit 17 ... Control circuit 18 ... Energization ON / OFF switching circuit 19 ... Energization control signal generation circuit 20 ... Status signal generation circuit

Claims (1)

[Claims] 1. A panel having a plurality of scanning lines, a drive circuit for driving each scanning line of the panel, a pen-shaped pointing device for pointing an arbitrary position on the panel, and the pointing device for pointing. A coordinate detection circuit that detects coordinates on the panel, a detection unit that detects that the pen tip of the pointing device has been pressed, and a power supply to the panel, the drive circuit, the pointing device, and the coordinate detection circuit. When the coordinate detection standby state continues for a predetermined time, the energization switching unit is turned off, and the detection unit detects that the pen tip of the pointing device is pressed. And a switching control means for switching the energization switching means to ON when the coordinate detection device is turned on.