JPH04308916A - Position detector - Google Patents

Abstract

PURPOSE:To realize an operating state in which a power consumption is reduced when a pausing period when the position of a position indicator is not detected continues, in the input detecting face of a position detector. CONSTITUTION:The position detector equipped with a position detecting face 19 which detects the position of the position indicator, is equipped with a pausing time detecting means 11 which detects whether or not a lapse time since the position detection is operated lastly is beyond a preliminarily set time, and a means (interrupting timer 10) which changes the processing interval of the position detection. When the pausing time detecting means detects that the lapse time is beyond the preliminarily set time, the processing operation whose power consumption is reduced is operated by widening the processing interval of the position detection by the means 10 which changes the processing interval, and the processing of the position detection is operated after immediately turning back to the normal processing interval at the time of detecting the position of the position indicator.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detection device such as a digitizer or tablet used in a data processing device.

0002

2. Description of the Related Art In conventional position detection devices, in order to save power consumption when the device is not in use, the power source is cut off by manually operating a power switch to put the entire device in a dormant state.

0003

[Problems to be Solved by the Invention] However, such conventional power consumption saving methods are cumbersome because the user has to operate a power switch to shut off the power. In addition, since the entire device is placed in a dormant state by cutting off the power supply, it takes time to start up the device when it is reused, and there is a problem that it cannot be used immediately.

The present invention has been devised to solve such conventional problems, and when the input detection surface of the position detection device continues to be idle for a predetermined period of time or more,
It is an object of the present invention to provide a position detection device that reduces power consumption by widening the processing interval of position detection and returning to the normal processing interval as soon as position detection starts on the input detection surface.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a position detecting device equipped with a position detecting surface for detecting the position of a position pointing tool. The apparatus includes a down time detection means for detecting whether or not the time has exceeded a preset time, and a means for reducing power consumption by changing a position detection processing interval. When it is detected that the processing interval has exceeded the processing interval, the processing interval of the processing interval changing means is increased to perform a processing operation that reduces power consumption, and when the position of the position pointing tool is detected, the processing operation is performed at the normal processing interval. It is composed of

[0006]

[Operation] In the position detection device, the pause time detection means measures the pause time after the last process of detecting the position of the position indicator on the position detection surface, and the pause time exceeds the preset time. When this occurs, the interval between processes for detecting the position of the position pointing tool is increased.

Furthermore, in a position detection device having a matrix-type position detection surface, the downtime after the last process of detecting the position of the position indicator is measured by the downtime detection means, and the downtime is measured by the downtime detection means. When a preset time is exceeded, a process is performed in which the electrode wires on the position detection surface are thinned out.

[0008] Then, when the position of the position indicator is detected,
Returns to position detection processing at normal processing intervals.

[0009]

【Example】

(First Embodiment) As shown in FIG. Switches 18a, 18b, 18c, which are controlled by control signals of
18d, and based on the voltage applied via the switches 18a and 18b, converts the analog voltages output from the switches 18c and 18d, which indicate the position in the X-axis and Y-axis directions, into digital signals and outputs them to the bus. A/D converters 15 and 16 are provided. Furthermore, the bus has a CPU
11, RAM 12, ROM 13, a timer 10 that generates an interrupt to the CPU 11 at preset intervals;
Serial communication controller (SCC) 14 for sending position detection data to an external device
is connected.

Based on voltages applied alternately from both the X-axis and Y-axis directions to the position detection surface 19, which is a resistor, via the switches 18a and 18b, the X-axis direction from the origin to the touch point is measured. The signal 11 corresponding to the distance is sent to switch 1.
A signal 12 corresponding to the distance in the Y-axis direction from the origin to the touch point is guided to the A/D converter 15 via switch 18d.

Next, the operation of the position detection device configured as described above will be explained based on the flowchart shown in FIG.

Step 21: In response to an interrupt from the timer 10, a position detection process is started. Step 22: The control circuit that determines the X-axis and Y-axis detection directions is operated, and the switches 18a, 18b, 18c, Step 23: The voltage values of the X-axis and Y-axis signals 11 and 12 are A/D converted to obtain X-axis and Y-axis position data.

Step 24: It is determined whether or not the position has been detected based on this position data. In this step, if the position pointing device is within the detection range of the input detection surface 19, proceed to step 25, and if the position pointing device is not within the detection range, proceed to step 28. Step 25: Detected Send the position data from the SCC 14, step 26; set the variable t to 0 so that it can be seen that the position was detected in this process, step 27
;Set so that the next timer 10 interrupt will occur at the normal processing interval.

Step 28: In step 24, if it is determined that the pause time is such that the position pointing device is not within the detection range of the input detection surface 19, add 1 to the variable t.Step 29: Set the variable t in advance. Compare it with a certain input waiting time T, and if t does not exceed T, terminate the interrupt processing as is, and if it exceeds T,
The interval for the next timer interrupt in step 2A is increased.

(Second Embodiment) As shown in FIG. 3, in a matrix type position detection device such as an electromagnetic induction type,
The position sensing surface 30 has electrode wires arranged in a matrix in the axial and Y-axis directions, and each electrode wire in the matrix in both axial directions is sequentially selected, and the voltage generated in each electrode wire is sequentially detected. It is equipped with multiplexers 33 and 34 that output, and A/D converters 15 and 16 that convert each analog voltage outputted through the multiplexers 33 and 34 into a digital signal and output it to the bus.
4 is controlled by a control circuit 17.

The position pointing device used in the electromagnetic induction matrix type position detection device generates a local magnetic field, and the matrix-shaped electrode wires brought close to this position pointing device induce an electromotive force. This electromotive force is guided to A/D converters 15 and 16 via multiplexers 33 and 34. Then, the electrode line with the maximum induced electromotive force is obtained as input position data.

Furthermore, the bus includes a CPU 11 and a RAM 1.
2. A ROM 13, a timer 10 that generates an interrupt to the CPU 11 at preset intervals, and a serial communication controller (SCC) 14 that sends position detection data to an external device are connected.

Next, the operation of the matrix type position detection device configured as described above will be explained based on the flowchart shown in FIG.

Step 40: In response to an interrupt from the timer 10, position detection processing is started. Step 41: It is determined whether the mode is thinning out mode or normal mode. At first, it is the normal mode, so go to No, set a multiplexer to the X-axis electrode line and Y-axis electrode line of the position detection surface 30, and change the voltage generated from each of the X-axis and Y-axis electrode lines to A/ D converters 15 and 16 convert it into a digital signal.

Step 43: It is determined whether or not the position has been detected based on the position data converted to the digital signal. In this step, if the position pointing device is within the detection range of the input detection surface 30, proceed to Yes and select SCC.
14, the variable t is set to 0 so that it can be seen that the position has been detected in the current process, and the normal mode is set so that the next interrupt of the timer 10 is performed at the normal process interval.

[0021] Further, in this step 43, if it is determined that the position pointing tool is not within the detection range of the input detection surface 30 during the pause time, the process proceeds to No and adds 1 to the variable t.
Step 45; Compare the variable t with a preset input waiting time T, and if t does not exceed T, interrupt processing is terminated; if it exceeds T,
Set thinning mode.

Step 42: If it is determined in step 41 that it is the thinning mode, the process advances to Yes, and it is calculated whether the current electrode wire number n is an integral multiple of the thinning interval M, and the integer If it has not doubled,
The electrode wires are thinned out and the process proceeds to step 46. For example, M
In the case of =2, the first, third, etc. electrode lines are thinned out. If the current electrode wire number n is an integral multiple of M and is not thinned out, the position voltage can be read and A
/D conversion is performed and the process advances to step 43.

Step 46: Check the relationship between the current electrode line number n and the maximum electrode line number (N-1) to determine whether or not processing of the entire screen has been completed. If finished, n=0
to return to the beginning of the screen, and if not finished, set 1 to n.
and proceed to processing the next electrode wire.

(Third Embodiment) The process of once every M times in the second embodiment is executed by shifting the electrode wire number every time the position detection for one screen is completed, thereby improving the precision of position detection. let The operation will be explained based on the flowchart of FIG.

The subsequent processing when it is determined in step 41 that the thinning mode is not in effect (No) is the same as that in the flowchart of FIG.

Step 52: If it is determined that the thinning mode is selected in step 41, the process advances to Yes, and the remainder of the current electrode wire number n is divided by the thinning interval M.
If so, the position voltage is read and A/D converted, and the process proceeds to step 43, position detection determination.

Step 53; In step 52, n/
If the remainder of M is not K, the relationship between the current electrode wire number n and the maximum electrode wire number (N-1) is checked to determine whether or not processing of the entire screen has been completed. If it is not finished,
Add 1 to n and proceed to process the next electrode line, and if completed, add 1 to K. Through this process, the electrode wire number for performing position detection for one screen next time will be shifted by one from the current electrode wire number. Step 54: Compare the thinning interval M and K, and K will be thinned out. If the interval M has been reached, set K=0 and return to the initial position.

In the above, the matrix type position detection surface is of the electromagnetic induction type. However, as a matrix type position detection surface, a voltage is sequentially applied to the X-axis electrode wires among the electrode wires in the matrix, and the position is detected. The present invention can also be applied to a digital position detection device that detects a position by detecting a Y-axis electrode line that generates a voltage when a pointing tool is pressed.

[0029]

As explained above, according to the position detection device of the present invention, when the input detection surface remains idle for a predetermined period of time or more, the processing time for position detection is automatically extended, and the input As soon as the position is detected on the detection surface, normal processing is resumed, so the average power consumption can be reduced, and when applied to a battery-powered portable device, the operating time can be extended.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a pressure-sensitive position detection device that is an embodiment of the present invention;

FIG. 2 is a flowchart for explaining the operation of the device shown in FIG. 1;

FIG. 3 is a block diagram showing a position detection device such as an electromagnetic induction type according to another embodiment of the present invention;

FIG. 4 is a flowchart for explaining the operation of the device shown in FIG. 3;

FIG. 5 is the first half of a flowchart for explaining other operations of the device shown in FIG. 3;

FIG. 6 is the second half of a flowchart for explaining another operation of the apparatus shown in FIG. 3;

[Explanation of symbols]

11 CPU 12 RAM 13 ROM 14 SCC 15, 16 A/D converter 17 Control circuit 18a-18d Switch 19, 30 Electromagnetic induction position detection surface 31, 32 decoder 33, 34 Multiplexer

Claims (3)

[Claims] Claim 1: In a position detection device equipped with a position detection surface that detects the position of a position pointing tool, a pause time for detecting whether the pause time since the last position detection has exceeded a preset time. and a means for changing the processing interval of position detection, and when it is detected from the output of the pause time detection means that a preset time has been exceeded, the processing interval is changed by the means for changing the processing interval. What is claimed is: 1. A position detection device characterized in that the position detection processing operation is performed with expanded position detection processing, and when the position of the position pointing tool is detected, the position detection processing operation is performed at normal processing intervals. 2. In a position detection device equipped with a matrix-type position detection surface that detects the position of a position pointing device, it is detected whether the pause time since the last position detection has exceeded a preset time. and processing change means for thinning out the electrode wires of the matrix-type position detection surface, and when the rest time detection means detects that a preset time has been exceeded. , a position detection device characterized in that the processing change means performs a processing operation in which the electrode wires are thinned out, and when the position of the position pointing tool is detected, the position detection processing operation is performed at a normal processing interval without thinning out the electrode wires. . [Claim 3] Claim 2, characterized in that the electrode line to be processed is shifted each time the processing of one screen is completed.
The position detection device described in .