JP2002215317A - Display device integrated type position-detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device integrated type position-detecting device which is hardly affected by noise produced from a display device side, and stably detecting coordinate values. SOLUTION: A detection unavailable period, wherein the scanning position of a display device is overlapped to a predetermined noise mixing area centered on the indicated position of a position indicator at that time, is calculated on the basis of the time of one vertical scanning of the display device; the corresponding relationship between a display part and a position detecting part, and the indicated position of the position indicator at that time; the calculated detection unavailable period is compared with the passage time information from the time of generation of the vertical synchronization signal of the display device outputted from a time measuring circuit 22; and the position detecting operation is stopped, when they match each other, to exclude the coordinate values having possibility of being affected by the noise from the display device side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting device integrated with a display device, in which a display portion of a display device and a position detecting portion of a position detecting device are integrally arranged.

[0002]

2. Description of the Related Art FIG. 1 schematically shows a display device integrated type position detecting device of this type.

In FIG. 1, reference numeral 101 denotes a position detecting device, for example, a position detecting portion of a position detecting device of a radio wave transmitting / receiving system disclosed in Japanese Patent Application Laid-Open No. 63-70326, and 201 denotes a display device, for example, a display image by a raster scan method. And a display unit of a well-known liquid crystal display having a planar shape, which are integrally arranged.

Reference numeral 102 denotes a control circuit (tablet controller) for the position detection device, and reference numeral 202 denotes a control circuit (liquid crystal controller) for the display device.
The position detecting unit 101 and the display unit 201 may be provided integrally. Reference numeral 103 denotes a position indicator of the position detecting device.

[0005] In the above-described position detecting device, radio waves are exchanged between the position detecting unit and the position indicator to obtain the coordinate value of the position indicated by the position indicator. According to this, a plurality of loop coils arranged side by side in the position detection direction in the position detection unit are sequentially selected to emit a radio wave, and a radio wave re-emitted from a resonance circuit provided in the position indicator is received. Then, the coordinate value (coordinate position) of the designated position is obtained from the distribution of the received signal strength.

[0006]

In the above-described position detecting device integrated with a display device, noise generated from the display unit, particularly noise due to a synchronization signal at the time of raster scanning, jumps into the loop coil of the position detecting unit. As a result, there is a problem that the coordinate values cannot be detected stably.

[0007] To alleviate this problem, conventionally, the influence of noise has been reduced by increasing the transmission power of radio waves on the position detecting device side. However, there is a limit even if the transmission power is increased, and there are problems such as an increase in cost.

The present invention provides a display-integrated position detecting device which is less susceptible to noise generated from a display device such as a liquid crystal display and can stably detect a coordinate value. The purpose is to.

Another object of the present invention is to provide a display-integrated position detecting device capable of detecting a stable coordinate value even with a small transmission power.

Another object of the present invention is to provide a display-integrated position detecting device capable of detecting stable coordinate values with a low-cost configuration.

[0011]

According to the present invention, in order to achieve the above object, a magnetic field or an electric field or a magnetic field or an electric field is applied between a display unit of a display device for forming a display image by a raster scan method and a position indicator and a position detection unit. In a display-integrated position detection device in which the position detection unit of a position detection device that detects an indicated position of a position indicator by exchanging an electromagnetic field is disposed integrally with the position detection unit, the sub-scanning direction of the display device Means for measuring the time elapsed from the time of occurrence of the synchronization signal, and outputting this time information, the time required for one sub-scan of the display device, the correspondence between the display unit and the position detection unit,
Means for calculating a period in which the scanning position of the display device overlaps within a predetermined range centered on the pointing position of the position indicator at that time from the pointing position of the position pointing device at that time; and Means for stopping the position detection operation of the position detection device in at least a direction coinciding with the sub-scanning direction of the display device during the period.

According to the above configuration, a scanning operation for detecting coordinates in the position detecting device, that is, a position detecting operation can be started based on the time information output from the time measuring means. The time information based on the generation time of the synchronization signal is related to the scanning position in the display device, and noise generated from this scanning position affects the coordinate detection. Therefore, in the present invention, based on the time information, based on information such as the scanning frequency and scanning direction of the display device and the location where the position indicator is placed, it is determined whether or not harmful noise is mixed in the coordinate detection at that time. to decide. When the scan area for coordinate detection coincides with the scan position of the display device, that is, the position where noise is generated, the start of scanning for coordinate detection is delayed. Is stopped, scanning is performed at a time when the noise occurrence position does not coincide with the coordinate detection position. By performing such processing, the detected coordinate values are not affected by noise radiated from the display device.

According to the present invention, in order to achieve the above object, a magnetic field, an electric field or an electromagnetic field is exchanged between a display unit of a display device for forming a display image by a raster scan method, and a position indicator and a position detection unit. A position detecting device for detecting a position indicated by a position indicator by integrally performing the operation of the synchronization signal in the sub-scanning direction of the display device. Means for measuring the time elapsed from the occurrence time and outputting this time information, the time required for one sub-scan of the display device, the correspondence between the display unit and the position detection unit, and the position indication at that time Means for calculating a period in which the scanning position of the display device overlaps within a predetermined range around the indicated position of the position indicator from the indicated position of the device, and the time information corresponds to the period. Was detected, characterized in that a means for disabling the data of the indication position of the direction corresponding to the sub-scanning direction of at least the display unit.

According to the above configuration, scanning for detecting coordinates is continuously performed at a constant cycle. On the other hand, based on time information based on the time of occurrence of the synchronization signal, harmful noise for coordinate detection is mixed at that time based on information such as the scanning frequency and scanning direction of the display device and the location of the position indicator. It is determined whether or not each coordinate detection scan. As a result, if the scan area for coordinate detection coincides with the scan position of the display device, that is, the noise occurrence position, the coordinate data is invalidated. By processing in this way,
Even though the detected coordinate data itself may be affected by noise, it is possible to exclude coordinate data that may be affected by the noise.

As described above, the influence of noise can be avoided by using the scanning synchronization signal of the display device because of the timing and period of the synchronization signal, the area scanned for coordinate detection, and the like. This is because it is possible to predict the timing at which is mixed.

A display device such as a liquid crystal display generally scans at high speed in the main scanning direction (horizontal direction) and scans at a low period of about several tens KHz in the sub-scanning direction (vertical direction), like a CRT. I have. For this reason, almost no noise is mixed into the loop coils (X-axis coils) arranged in the horizontal direction, and the loop coils (Y
Noise is mixed into the shaft coil). In such a case, it is preferable to make a determination based on the timing of the vertical synchronizing signal, particularly aiming at the time of scanning the Y coordinate.

Further, according to the present invention, the time measuring means described above is not particularly provided, and the generation time of the synchronization signal in the sub-scanning direction of the display device, the time required for one sub-scanning of the display device, the display section and the position Means for identifying a period during which the display device scans within a predetermined range centered on the indicated position of the position indicator from the corresponding relationship with the detection unit and the indicated position of the position indicator at that time; and Means for stopping the position detection operation of the position detection device in at least the direction coinciding with the sub-scanning direction of the display device during the specified period, or at least the sub-display of the display device detected during the specified period. In the same manner as described above, the influence of noise can be avoided by providing a means for invalidating the data at the designated position in the direction coinciding with the scanning direction.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] (Configuration of First Embodiment) FIG. 2 shows a first embodiment of a display-integrated position detecting device according to the present invention. .

In FIG. 2, reference numeral 1 denotes a position detecting unit, in which a plurality of, for example, 40 loop coils are arranged as loop coils X1 to X40 and loop coils Y1 to Y40 in the X-axis direction and the Y-axis direction, respectively. Has become. These loop coils are connected to a selection circuit 2 for selecting each loop coil.

Each loop coil of the position detector 1 is formed on a printed circuit board (not shown) by etching or the like.
For example, a display unit of a well-known planar liquid crystal display that forms a display image by a raster scan method, and a coordinate detection area and a display area by the loop coils are arranged so as to be exactly the same area.

The selection circuit 2 is connected to a transmission / reception switching circuit 3, the receiving side (R) of the transmission / reception switching circuit 3 is connected to an amplifier 4, and the amplifier 4 is connected to a detection circuit 5. The detection circuit 5 is connected to a low-pass filter 6, which is connected to a sample-and-hold circuit 7. The sample-hold circuit 7 is connected to an A / D conversion circuit 8, and the A / D conversion circuit 8 is connected to a CPU (central processing unit) 9.

An oscillator 10 generates an AC signal having a constant frequency f0, and a current driver 11 converts the AC signal into a current. The output of the driver is connected to the transmission side (T) of the transmission / reception switching circuit 3. An AC magnetic field having a frequency f0 is radiated from one selected loop coil in the position detector 1.

The CPU 9 transmits a control signal (information) to the selection circuit 2, the transmission / reception switching circuit 3, the sample and hold circuit 7, and the A /
The data is sent to the D conversion circuit 8.

The control circuit (tablet controller) of the position detecting device is constituted by the elements denoted by reference numerals 2 to 11.
Is configured.

Reference numeral 12 denotes a position indicator, in which a coil 13, a pen pressure sensor 14, and a pen pressure detecting circuit 15 are provided.
Is provided. The coil 13 is connected to a capacitor (not shown) to form a resonance circuit having a frequency f0. The writing pressure detection circuit 15 is configured by an electronic circuit including an IC,
An analog signal from the pen pressure sensor 14 is converted into a time-division digital signal, and the digital signal is returned to the position detecting unit 1 through the coil 13. The operation of this position indicator is disclosed in, for example, Japanese Patent Application Laid-Open No. 5-313439, and will not be described here.

The configuration up to this point is almost the same as that of the display device integrated type position detecting device described in the prior art.

In FIG. 2, reference numeral 21 denotes a liquid crystal controller for driving the display section of the liquid crystal display, which is a conventionally known liquid crystal controller. In the present embodiment, a vertical synchronization signal is extracted from the liquid crystal controller 21 and supplied to the time measurement circuit 22. The time measuring circuit 22 sequentially supplies the elapsed time from the generation of the vertical synchronizing signal to the CPU 9 as a digital value, and comprises a clock oscillator and a counter circuit. These configurations are one of the features of the present invention.

(Operation of First Embodiment) First, a full-surface scanning operation is performed to roughly detect the position of the position indicator 12 on the position detector 1. In this full scan operation, while sequentially switching all of the 40 loop coils in each of the X-axis direction and the Y-axis direction, it is detected whether a signal level equal to or higher than a predetermined threshold is received.
This full-surface scanning operation is for first detecting approximately where the position indicator 12 is located, so that the influence of noise from the liquid crystal display side does not matter. Therefore, it is performed in the same manner as in the case of the conventional apparatus.

Next, a description will be given of a partial scanning operation after the approximate position of the position indicator 12 has been found by the above-described overall scanning operation. The liquid crystal display used here scans at high speed in the horizontal direction (X-axis direction), and scans vertically (Y-axis direction) from top to bottom at a speed of about 60 Hz (once every 17 ms). And Also,
The X-axis coordinate and the Y-axis coordinate are detected by the position indicator 12 respectively.
Is detected by a method similar to the conventional method by scanning several loop coils before and after the loop coil (peak coil) that is closest to the position where is located, that is, the loop coil (peak coil) having the highest signal level. Is about 1 ms for each axis.

FIG. 3 shows the state of the partial scanning operation in the present embodiment. In FIG. 3, the vertical synchronization signal, the vertical scanning position on the display screen of the liquid crystal display (this is the time This is a value recognized by the CPU 9 based on information from the measurement circuit 22.) and timings of an X-axis partial scan operation and a Y-axis partial scan operation for position detection.

As the position detecting operation, the X-axis partial scan and the Y-axis partial scan are repeated.
When the liquid crystal display is scanning within a predetermined range (noise mixing area) in the Y-axis direction centered on the designated position 2, noise is mixed into the loop coil in the Y-axis direction in that area as described above. For this reason, during this period, the passage of the noise is waited without performing the partial scan (at least the Y-axis partial scan). Therefore, the coordinate value of the indicated position can be detected without being affected by noise from the liquid crystal display.

The actual operation is performed by the CPU 9 in the time required for one sub-scan of the liquid crystal display, the correspondence between the display unit of the liquid crystal display and the position detecting unit 1, and the position indicated by the position indicator 12 at that time. (Peak coil number)
From this, a period during which the scanning position of the liquid crystal display overlaps within a predetermined range centered on the position indicated by the position indicator 12 at that time (undetectable period) is calculated, and the time information from the time measuring circuit 22 is calculated. The partial scan operation is stopped if the period is not within the undetectable period, and the partial scan operation is performed if the period is not within the undetectable period, and a detailed coordinate value of the designated position is obtained in the same manner as in the related art.

FIG. 4 shows a processing flow of the position detecting operation in the first embodiment described above.

(Expansion of First Embodiment) In this embodiment, a liquid crystal display is used as a display device, but the present invention can be applied to other types of display devices such as a plasma display and an organic EL display. . Further, in the present embodiment, the loop coil is formed on the printed circuit board, but this may be incorporated in the liquid crystal display.

In this embodiment, the X-axis scan and the Y-axis scan are performed.
Although only the axis scan is repeated, a period of pen pressure detection as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. Hei 5-313439 may be added to this. In this case, the pen pressure value from the position indicator is received as digital data, so that it is hardly affected by noise. Therefore, there is no problem that the writing pressure detection period coincides with the noise mixing period.

[Second Embodiment] (Configuration of Second Embodiment) The device configuration of the second embodiment is the same as that of the first embodiment shown in FIG. .

(Operation of the Second Embodiment) First, as in the case of the first embodiment, a full-surface scan for roughly detecting the position of the position indicator 12 on the position detector 1 as in the case of the first embodiment. The operation is performed, and then the operation shifts to the partial scan operation as in the first embodiment.

FIG. 5 shows the state of the partial scan operation in the present embodiment.
The following description is based on the assumption that the device operates under the same conditions as those of the embodiment. That is, the liquid crystal display scans at a high speed in the horizontal direction (X-axis direction) and scans at a speed of about 60 Hz (once every 17 ms) from top to bottom in the vertical direction (Y-axis direction). I do. Further, the detection of the X-axis coordinate and the Y-axis coordinate is performed by detecting several loop coils that are closest to the position where the position indicator 12 is placed, that is, around the loop coil (peak coil) having the highest signal level. By scanning, coordinate detection is performed in the same manner as in the related art, and the time required for this scan is about 1 ms for each axis.

In FIG. 5, from the top, a vertical synchronization signal,
The vertical scanning position on the display screen of the liquid crystal display (this is a value recognized by the CPU 9 based on information from the time measuring circuit 22), the X-axis partial scanning operation for position detection, and the Y-axis partial scanning operation The timing is shown.

In the position detection operation, the X-axis partial scan and the Y-axis partial scan are performed at a fixed interval (in the present embodiment, 2 intervals).
ms), but a predetermined range in the Y-axis direction centered on the position indicated by the position indicator 12 (noise mixing region)
When the partial scan is performed during the period when the liquid crystal display scans the inside, the CPU 9 performs a process to invalidate at least the data by the Y-axis partial scan. Therefore, the coordinate value of the indicated position can be obtained without being affected by noise from the liquid crystal display.

In the actual operation, the CPU 9 repeatedly performs the conventional X-axis partial scan and the Y-axis partial scan to obtain the coordinate values, the time required for one sub-scan of the liquid crystal display, and the time required for the liquid crystal display. From the correspondence between the display unit and the position detection unit 1 and the pointed position (peak coil number) of the position indicator 12 at that time, a predetermined range centered on the pointed position of the position indicator 12 at that time Within this period, a period during which the scanning position of the liquid crystal display overlaps (a non-detection period) is calculated, and this is compared with the time information from the time measurement circuit 22. If not within the undetectable period, the coordinate values of the X axis and the Y axis are also valid.

FIG. 6 shows a processing flow of the position detecting operation in the second embodiment described above.

(Expansion of Second Embodiment) In this embodiment, a liquid crystal display is used as a display device, but the present invention can be applied to other types of display devices such as a plasma display and an organic EL display. . Further, in the present embodiment, the loop coil is formed on the printed circuit board, but this may be incorporated in the liquid crystal display.

In this embodiment, X-axis scanning and Y-axis scanning are performed.
Although only the axis scan is repeated, a period of pen pressure detection as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. Hei 5-313439 may be added to this. In this case, the pen pressure value from the position indicator is received as digital data, so that it is hardly affected by noise. Therefore, there is no problem that the writing pressure detection period coincides with the noise mixing period.

In the first and second embodiments, the time measurement circuit 22 creates information on the elapsed time since the generation of the vertical synchronization signal, and the CPU 9 receives the information and compares it with the undetectable period. The CPU 9 directly receives the vertical synchronization signal from the liquid crystal controller 21 and determines the timing and the correspondence between the display unit and the position detection unit 1 of the liquid crystal display. Relationship and position indicator 12 at that time
From the indicated position (the number of the peak coil), a period during which the liquid crystal display scans within a predetermined range centered on the indicated position of the position indicator 12 at that time (undetectable period) is specified. During the period, the partial scan operation at least in the direction corresponding to the sub-scanning direction of the liquid crystal display is stopped, or the data of the designated position at least in the direction corresponding to the sub-scanning direction of the liquid crystal display detected during the specific period is invalidated. By doing so, the same effect as described above can be obtained.

FIGS. 7 and 8 show the processing flow of the position detection operation in the first and second embodiments in this case, respectively.

[0047]

As described above, according to the present invention,
The scanning area for coordinate detection is the scanning position of the display device,
That is, when the position coincides with the noise occurrence position, the scan operation for detecting the coordinates is stopped, or the coordinate values obtained by the scan operation for detecting the coordinates are invalidated, so that the noise radiated from the display device is reduced. Can be detected.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an outline of a display device integrated type position detection device.

FIG. 2 is a configuration diagram showing a first embodiment of the present invention.

FIG. 3 is a diagram showing a partial scan operation according to the first embodiment of the present invention;

FIG. 4 is a flowchart of a process of a position detection operation according to the first embodiment.

FIG. 5 is a diagram illustrating a partial scan operation according to the second embodiment of the present invention;

FIG. 6 is a flowchart of a process of a position detection operation according to the second embodiment.

FIG. 7 is a flowchart of another position detecting operation according to the first embodiment;

FIG. 8 is a flowchart of another position detecting operation according to the second embodiment;

[Explanation of symbols]

1: position detection unit, 2: selection circuit, 3: transmission / reception switching circuit,
4: amplifier, 5: detection circuit, 6: low-pass filter,
7: sample and hold circuit, 8: A / D conversion circuit, 9:
CPU, 10: oscillator, 11: current driver, 12: position indicator, 13: coil, 14: writing pressure sensor, 15: writing pressure detection circuit, 21: liquid crystal controller, 22: time measurement circuit.

Claims (5)

[Claims] 1. A pointing unit of a position indicator by exchanging a magnetic field, an electric field, or an electromagnetic field between a display unit of a display device that forms a display image by a raster scan method and a position indicator and a position detecting unit. In a display-integrated position detection device in which the position detection unit of the position detection device to be detected is integrally superposed and arranged, the time elapsed from the generation time of the synchronization signal in the sub-scanning direction of the display device is measured. Means for outputting the time information, the time required for one sub-scan of the display device, the correspondence between the display unit and the position detection unit, and the position indicated by the position indicator at that time. Means for calculating a period in which the scanning position of the display device overlaps within a predetermined range centered on the position indicated by the position indicator of the position indicator, and at least display on the position detection device while the time information corresponds to the period. Means for stopping a position detection operation in a direction coinciding with the sub-scanning direction of the apparatus. 2. A display unit for forming a display image by a raster scan method, and a magnetic field, an electric field, or an electromagnetic field is exchanged between a position indicator and a position detector, thereby indicating a position indicated by the position indicator. In a display-integrated position detection device in which the position detection unit of the position detection device to be detected is integrally superposed and arranged, the time elapsed from the generation time of the synchronization signal in the sub-scanning direction of the display device is measured. Means for outputting the time information, the time required for one sub-scan of the display device, the correspondence between the display unit and the position detection unit, and the position indicated by the position indicator at that time. Means for calculating a period during which the scanning position of the display device overlaps within a predetermined range centered on the position indicated by the position indicator of the position indicator, and at least a sub-display of the display device detected while the time information corresponds to the period. Means for invalidating data of a designated position in a direction coinciding with the scanning direction. 3. A display unit for forming a display image by a raster scan method, and a magnetic field, an electric field, or an electromagnetic field is exchanged between a position indicator and a position detector to determine a position indicated by the position indicator. In a display-integrated position detecting device in which the position detecting unit of the position detecting device to be detected is integrally superimposed and arranged, the time of occurrence of a synchronization signal in the sub-scanning direction of the display device and one time of the display device From the time required for the sub-scanning, the correspondence between the display unit and the position detection unit, and the indicated position of the position indicator at that time, a predetermined range around the indicated position of the position indicator at that time is determined. Means for specifying a period during which the display device scans, and means for stopping the position detection operation in the position detection device at least in a direction coinciding with the sub-scanning direction of the display device during the specified period. Display-integrated type position detecting device according to symptoms. 4. A pointing unit of a position indicator by exchanging a magnetic field, an electric field, or an electromagnetic field between a display unit of a display device that forms a display image by a raster scan method and a position indicator and a position detecting unit. In a display-integrated position detecting device in which the position detecting unit of the position detecting device to be detected is integrally superimposed and arranged, the time of occurrence of a synchronization signal in the sub-scanning direction of the display device and one time of the display device From the time required for the sub-scanning, the correspondence between the display unit and the position detection unit, and the indicated position of the position indicator at that time, a predetermined range around the indicated position of the position indicator at that time is determined. Means for specifying a period during which the display device scans, and means for invalidating data of an indicated position detected at least in a direction coinciding with the sub-scanning direction of the display device detected during the specified period. Especially Display-integrated type position detecting device according to. 5. The position detecting device integrated with a display device according to claim 1, wherein a flat liquid crystal display is used as the display device.