JP3587391B2 - Position detection device - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a position detection device that detects a designated position on a flat plate.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is a position detecting device for detecting an indicated position on a flat plate as shown in FIG.
[0003]
This position detecting device comprises a plurality of column electrodes X which are insulated and arranged in parallel.₁, X₂, ...,X _m (Collectively indicated by the symbol X) and a plurality of row electrodes Y arranged in parallel and perpendicular to the column electrodes₁, Y₂, ...,Y _n A substrate 1 on which a column electrode X is applied with a column electrode scanning signal, and a row electrode Y which applies a row electrode scanning signal to the row electrode Y A drive unit 3, a detection pen 4 for detecting each scanning signal applied to the column electrode X or the row electrode Y, and coordinates for determining the tip coordinates of the detection pen 4 based on the detection signal output from the detection pen A determination unit 5 and a control unit 8 that controls the operations of the column electrode driving unit 2 and the row electrode driving unit 3 are schematically configured.
[0004]
The control unit 8 sends the column electrodes X and the row electrodes Y to the column electrode driving unit 2 and the row electrode driving unit 3 by sending scanning signals x and y having pulse voltages with a predetermined time difference as shown in FIG. Scan. At the same time, a control signal is sent to the column electrode drive unit 2, the row electrode drive unit 3, and the coordinate determination unit 5 to notify that the column electrode X or the row electrode Y is being scanned. The column electrode driving section 2 and the row electrode driving section 3 have gates for outputting or cutting off signals. The signal from the control unit 8 closes the gate of the row electrode driving unit 3 while scanning the column electrode X, and closes the gate of the column electrode driving unit 2 while scanning the row electrode Y. close.
[0005]
In this manner, the pulse voltage that has passed through the gates of the column electrode driving unit 2 and the row electrode driving unit 3 is sequentially applied to the column electrodes X₁, X₂, ...,X _m And row electrode Y₁, Y₂, ..., Y_nTo scan the column electrode X and the row electrode Y. On the other hand, the coordinate determination unit 5 determines the tip coordinates of the detection pen 4 based on the detection signals detected by the X coordinate detection circuit 6 and the Y coordinate detection circuit 7 and the control signal from the control unit 8.
[0006]
Next, as another position detecting device to which the above-described position detecting device is applied, a position detecting device as shown in FIG. 9 is disclosed in Japanese Patent Publication No. 50-10088.
[0007]
This position detecting device includes a column electrode X and a row electrode Y, which are insulated from each other and are arranged in parallel, delay circuits 11 and 12 including an inductance L and a capacitor C, and a column electrode X via the delay circuits 11 and 12. And different frequencies f applied to the row electrodes Y_x, F_ySignal generator F that generates a voltage signal of_x, F_yAnd a coordinate determination unit 14 that determines the tip coordinates of the detection pen 13 based on the detection signal from the detection pen 13. Voltage signals having different phases are applied to the respective column electrodes X and the respective row electrodes Y by the delay circuits 11 and 12 according to their positions. Therefore, the frequencies f having different phases depending on the detection pen 13_x, F_yIs detected, and this detection signal and the transmitter F_x, F_yBy comparing the phase with the output signal of the detection pen 13 by the x-coordinate detection circuit 15 and the Y-coordinate detection circuit 16 of the coordinate determination unit 14, the tip coordinates of the detection pen 13 can be detected.
[0008]
Further, there is a position detecting device integrated with a display device. In the case of this position detection device, for example, a column electrode driving unit and a row electrode driving unit that output scanning signals x and y are provided to row electrodes and column electrodes in an active matrix display panel used as a display device, By detecting the scanning signals x and y with the detection pen, the coordinates of the tip of the detection pen can be detected.
[0009]
[Problems to be solved by the invention]
However, the conventional position detecting device has the following problems.
[0010]
That is, in the position detection device shown in FIGS. 7 and 9, as a basic configuration, a plurality of column electrodes and a plurality of row electrodes, and an electrode drive circuit that applies some scanning signal to each of the electrodes to drive the electrodes. In addition, a control circuit for controlling the electrode driving circuit is required. Therefore, when performing more accurate position detection, a greater number of column electrodes and row electrodes are required, and the electrode driving circuit and the control circuit are complicated. This is the same in the case of the position detecting device disclosed in Japanese Patent Publication No. 50-10088.
[0011]
Furthermore, when, for example, a capacitive coupling pen is used as a detection pen for detecting the scanning signal applied to each of the above-described electrodes, the detection accuracy of the scanning signal applied to the upper column electrode and the detection accuracy of the scanning signal applied to the lower side are reduced. Different from the detection accuracy, when the detection pen is inclined and brought into contact with the display screen, an error occurs in the detection position.
[0012]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a position detecting device capable of detecting the coordinates of any one specified point with high accuracy with a simple structure. .
[0013]
[Means for Solving the Problems]
The position detection device of the present inventionA plurality of pixel electrodes arranged in a matrix, a counter electrode facing the plurality of pixel electrodes, and a liquid crystal provided between the plurality of pixel electrodes and the counter electrode form a pixel matrix. It is configuredA position detecting device integrated with an active matrix type liquid crystal display panel, a signal generating member having a signal generator for generating a position detecting signal and an electrode for outputting a position detecting signal from the signal generator A conductive film having a uniform resistance component, an inductance component, and a capacitance component, and having a first signal detection electrode and a second signal detection electrode at two mutually different points near the periphery;A position detection signal generated from the signal generator;In response to indicating an arbitrary point on the conductive film by the signal generating member, the position detection signal from the signal generator applied to the conductive film is applied to the first signal detection electrode and the first signal detection electrode. With two signal detection electrodesRespectivelyDetectedBased on each phase difference with each detection signal,Coordinate determining means for determining the coordinates of the point indicated by the signal generating member, wherein the conductive film is formed on the active matrix type liquid crystal display panel.SaidAn opposing electrode, wherein the electrode of the signal generating member is electrostatically coupled to the conductive film to induce an induced voltage on the conductive film, and further detects a position generated by the signal generator. SignalSaidLCD panel displayToHas no effectAs described above, a pulse signal of a voltage that does not change the liquid crystal due to a change in a voltage difference between the picture element electrode and the counter electrode due to the application of the position detection signal to the conductive film.Thus, the above object is achieved.
[0020]
[Action]
BookAccording to the present invention, the position detection signal from the signal generator is applied to an arbitrary point on the conductive film by the signal generating member. The position detection signal propagates on the conductive film, and is detected by a first signal detection electrode and a second signal detection electrode provided at two different points near the periphery of the conductive film. A detection signal and a second detection signal are output.
[0021]
Thus, based on the position detection signal from the signal generator, the position detection signal applied by the coordinate determination means via the signal generation member propagates on the conductive film and the first signal detection electrode and the second signal detection electrode. The propagation time until the signal is detected by the signal detection electrode is detected, and the coordinates of the point specified by the tip of the signal generation member are determined.
[0022]
the aboveWhen the coordinate of the tip of the signal generating member is detected by the coordinate determining means, first, the phase of the position detection signal from the signal generator is compared with the phase of the first detection signal by the phase comparator. A first position information signal representing a phase difference corresponding to the propagation time is generated, and a phase of the position detection signal from the signal generator and a phase of the second detection signal are compared to obtain a position corresponding to the propagation time. A second position information signal representing the phase difference is generated. Then, next, the coordinate determining unit obtains a ratio between the maximum phase difference of the signal propagating through the conductive film and the detected phase difference based on the first and second position information signals. Is used to determine the coordinates of the tip of the signal generating member on the conductive film.
[0023]
signalWhen the tip of the generating member comes into contact with the conductive film, a position detection signal propagating through the conductive film is applied by a conductive electrode provided at the tip of the signal generating member. Thereafter, the position detection signal is detected by the first signal detection electrode and the second signal detection electrode provided on the conductive film, and the tip coordinates of the signal generation member are determined based on the detection signal.
[0024]
the aboveThe tip of the signal generating member and the conductive filmIsThe induced voltage is induced on the conductive film due to the electrostatic coupling and the signal voltage of the signal generating member. Thereafter, the position detection signal is detected by the first signal detection electrode and the second signal detection electrode provided on the conductive film, and the tip coordinates of the signal generation member are determined based on the detection signal.
[0025]
the aboveThe position detection signal propagated on the conductive film.IsThe first signal detection electrode and the second signal detection electrode provided on two adjacent sides of the conductive film respectively detect the coordinates of the tip of the signal generating member based on the detection signal.
[0026]
the aboveAn image is displayed on the display panel by the display device based on the tip coordinates of the signal generating member determined by the coordinate determining means, and the image is displayed at a position designated by the signal generating member.
[0027]
Active matrix typeThe signal voltage applied to and propagated by the signal generating member to the opposing electrode in the liquid crystal display panel is detected by the first signal detection electrode and the second signal detection electrode.WhenThe coordinates of the tip of the signal generating member are determined by the coordinate determining means based on the detection signals from these electrodes. Then, the designated position of the signal generating member on the liquid crystal display panel is displayed on an image based on the determined tip coordinates of the signal generating member.
[0028]
【Example】
Hereinafter, a position detecting device according to an embodiment of the present invention will be described in detail with reference to the illustrated embodiment. However, the present invention is not limited to the following embodiments.
[0029]
(First embodiment)
FIG. 1 is a diagram showing a position detecting device in the present embodiment, and shows a basic configuration of the position detecting device of the present invention. 1 includes a pulse generator 21, a conductive film 22, a signal generation pen 23, a first signal detection electrode 24, a second signal detection electrode 25, a first phase comparator 26, and a second phase comparator 27. , And a coordinate determination unit 28.
[0030]
The pulse generator 21 generates a pulse signal having a predetermined period, and applies the pulse signal to the conductive film 22 having a rectangular shape from the tip of the signal generating pen 23. The first signal detection electrode 24 and the second signal detection electrode 25 detect the pulse signal applied to the conductive film 22 and send out the detection signal to the first phase comparator 26 and the second phase comparator 27. The first phase comparator 26 and the second phase comparator 27 compare the phase difference between the pulse signal from the pulse generator 21 and the detection signals from the first signal detection electrode 26 and the second signal detection electrode 27, respectively. A first position information signal S1 and a second position information signal S2 are generated. Then, the coordinate determination unit 28 determines the tip coordinates of the signal generating pen 23 based on the first position information signal S1 and the second position information signal S2 obtained by the first phase comparator 26 and the second phase comparator 27. And output a coordinate signal.
[0031]
Hereinafter, the above will be described in more detail.
[0032]
The pulse signal output from the pulse generator 21 is applied to an arbitrary point on the conductive film 22 by the signal generating pen 23. The conductive film 22 is a transmission system having a uniform resistance component, an inductance component, and a capacitance component. A pulse signal applied to the conductive film 22 from the signal generating pen 23 is applied from the signal application point (a) to the entire surface of the film. Spread uniformly. At this time, the waveform of the pulse signal propagating on the conductive film 22 has a phase difference with the original pulse signal Sp having the period T shown in FIG. 3A as shown in FIG. 3B. It becomes a waveform.
[0033]
In this manner, the pulse signal propagating on the conductive film 22 includes the first signal detection electrode 24 and the second signal detection provided at two different points (b) and (c) where the conductive film 22 is adjacent to each other at the four corners. It is detected by the electrode 25. The first detection signal detected by the first signal detection electrode 24 has a waveform as shown in FIG. 3B, and the first phase comparator 26 generates the first detection signal waveform and the pulse waveform of the pulse generator 21. To obtain a first position information signal. On the other hand, the second detection signal detected by the second signal detection electrode 25 has a waveform as shown in FIG. 3E, and the second phase comparator 27 compares the second detection signal waveform with the pulse generator 21. The second position information signal is obtained from the pulse waveform.
[0034]
Next, a method of generating a position information signal performed by the first phase comparator 26 and the second phase comparator 27 will be described.
[0035]
FIG. 2 shows a possible configuration of the first and second phase comparators 26 and 27. However, FIG. 2 illustrates the first phase comparator 26. The first and second phase comparators 26 and 27 have a Schmitt trigger circuit 29 and an AND circuit 30. Hereinafter, the operation of the first phase comparator 26 will be described with reference to FIGS.
[0036]
A pulse signal Sp having a pulse waveform having a period T as shown in FIG. 3A sent from the pulse generator 21 to the first phase comparator 26 is applied to the input terminal of the AND circuit 30. Further, the detection signal of the pulse signal detected by the first signal detection electrode has a phase difference and a rounding as shown in FIG. 3B, and is applied to the input terminal of the Schmitt trigger circuit. Then, a pulse signal having a waveform having the same period T as the pulse signal Sp as shown in FIG. 3C is output from the Schmitt trigger circuit 29 and applied to the other input terminal of the AND circuit 30. Here, the pulse signal from the Schmitt trigger 29 is longer than the original pulse signal in the distance (b) between the pulse signal application point (a) of the conductive film 22 and the first signal detection electrode (in the second signal detection electrode). When detecting, the phase is delayed according to the distance (c). Therefore, the AND circuit 30 obtains the first position information signal S1 shown in FIG. 3D in which the phase difference between the pulse signal from the pulse generator 21 and the pulse from the Schmitt trigger circuit 29 is pulse width modulated. . When the signal is detected by the second signal detection electrode 27, a second position information signal S2 shown in FIG. 3G is obtained.
[0037]
The first and second position information signals S1 and S2 obtained as described above are sent to a coordinate determining unit 28, and the coordinate determining unit 28 determines the maximum value of the phase delay of the signal propagating through the conductive film 22 and the respective values. From the ratio of the detection signal based on the position information signals S1 and S2 to the phase delay, the X and Y coordinates of the contact position on the conductive film 22 with which the tip of the signal generating pen 23 contacts are determined, and the coordinate signal S3 is output. Is done.
[0038]
As described above, in this embodiment, the position detection signal output from the pulse generator 21 is applied to an arbitrary point on the conductive film 22 via the signal generation pen 23. Then, the phase difference between the detection signal detected by the first and second signal detection electrodes 24 and 25 of the conductive film 22 and the pulse signal Sp from the pulse generator 21 is detected, and the signal generation pen on the conductive film 22 is detected. The first and second position information signals S1 and S2 representing the coordinates of the 23 tips are generated. Thereby, the coordinate determination unit 28 detects the tip coordinates of the signal generating pen 23 based on the first and second position information signals S1 and S2 from the first and second phase comparators 26 and 27. . Therefore, the tip coordinates of the signal generating pen 23 can be detected with high accuracy with a very simple structure in which a pulse signal is sequentially and repeatedly applied to the conductive film 22 having the two signal detection electrodes 24 and 25.
[0039]
(Second embodiment)
This embodiment is an embodiment in which the first and second signal detection electrodes in the first embodiment are provided on two adjacent sides of the conductive film so as to extend over substantially the entire length of the two sides. FIG. 4 is a block diagram illustrating the position detection device according to the present embodiment.
[0040]
4 includes a pulse generator 31, a conductive film 32, a signal generating pen 33, an X-direction signal detection electrode 34, a Y-direction signal detection electrode 35, an X-direction counter 36, a Y-direction counter 37, and a coordinate determination unit. 38, the configuration is the same as in the first embodiment.
[0041]
The pulse generator 31, the conductive film 32, and the signal generating pen 33 have the same structure as the pulse generator 21, the conductive film 22, and the signal generator 23 shown in FIG. 1, and operate as described in the first embodiment. As a result, a pulse signal is applied to the conductive film 33. The X-direction signal detection electrode 34 and the Y-direction signal detection electrode 35 transmit the detection signal to the X-direction counter 36 and the Y-direction counter 37 at the same time when the pulse signal applied to the conductive film 32 reaches the electrode on one side. As a result, the X-direction counter 36 starts counting at the same time as inputting the pulse signal from the pulse generator 31, and waits until the detection signal from the X-direction detection electrode 34 is received, that is, from the signal application point (d) to the X-direction. The propagation time (e) of the pulse signal along the X direction to the signal detection electrode 34 is detected, and an X direction position detection signal is generated. On the other hand, the Y-direction counter 37 starts counting at the same time as inputting the pulse signal from the pulse generator 31, and waits for a detection signal from the Y-direction signal detection electrode 35, that is, from the signal application point (d) to the Y-direction. The Y-direction propagation time (f) of the pulse signal to the signal detection electrode 35 is detected to generate a Y-direction position detection signal.
[0042]
The X and Y direction position detection signals obtained as described above are sent to the coordinate determining means 38, and the pulse signal obtained by the X and Y direction counters 36 and 37 by the coordinate determining means 38 is propagated in the X and Y directions. From the comparison between the time and the maximum propagation time in the X and Y directions by the conductive film 32, the X and Y coordinates of the tip of the signal generating pen 33 can be obtained by the same calculation as in the first embodiment.
[0043]
Therefore, according to the present embodiment, it is not necessary to perform complicated calculations when determining coordinates, and high-accuracy position detection can be performed by simple ratio calculation.
[0044]
(Third embodiment)
This embodiment is a more specific embodiment in which the basic configuration shown in the first embodiment is combined with a display device. The position detecting device shown in the present embodiment is a position detecting device that enables an image based on the obtained coordinate detection signal to be displayed on a display device, and has a configuration as shown in FIG.
[0045]
The pulse generator 41, the conductive film 42, the signal generation pen 43, the first signal generation electrode 44, the second signal detection electrode 45, the first phase comparator 46, the second phase comparator 47, and the coordinate determination unit 48 are shown in FIG. The same as the pulse generator 21, conductive film 22, signal generation pen 23, first signal detection electrode 24, second signal detection electrode 25, first phase comparator 26, second phase comparator 27, and coordinate determination unit 28 shown in FIG. It has a structure and a mutual connection relationship, and operates as described in the first embodiment to detect the tip coordinates of the signal generating pen 43.
[0046]
The conductive film 42 is formed to be transparent, and the display content of the display panel 50 of the display device stacked under the conductive film 42 can be seen through the conductive film 42. The display control unit 49 controls the display device based on the X and Y coordinate signals indicating the tip coordinates of the signal generating pen 43 from the coordinate determination unit 48 and, as an example, the tip coordinates of the signal generating pen 43 on the display panel 50. Display points.
[0047]
As a result, the signal generation pen 43 slides on the conductive film 42, so that graphic input and graphic detection can be performed.
[0048]
At this time, the conductive film 42 laminated on the display panel 50 is formed of one thin film. Therefore, the display device of the present embodiment is thinner and simpler than the prior art display device in which the position detection device having the column electrodes and the row electrodes arranged in two layers crossing each other is integrated with the display panel. It can be configured.
[0049]
Further, also in an embodiment in which the basic configuration shown in the second embodiment is combined with a display device, a position detection device integrated with the display panel in the present embodiment as described above can be provided.
[0050]
(Fourth embodiment)
This embodiment is an embodiment in which an active matrix type liquid crystal display device is used as the display device in the third embodiment.
[0051]
FIG. 6 is a schematic block diagram of the position detecting device of the present embodiment, which is incorporated in an active matrix type liquid crystal display device.
[0052]
This display device includes an active matrix type liquid crystal display panel (hereinafter, simply referred to as a display panel) 51, and a display control circuit for supplying a display control signal to a row electrode driving circuit 52 and a column electrode driving circuit 53 for driving the display panel 51. 54, a coordinate detection circuit 56 for receiving detection signals from the first position detection electrode 67 and the second position detection electrode 68 and detecting the coordinates of the tip of the signal generating pen 55 on the display panel 51, and a pulse signal for detecting the coordinates. , A coordinate detection circuit 56 controlled by the display control circuit 54, and a control unit 58 controlling the pulse generator 57.
[0053]
The display panel 51 has a plurality of row electrodes G1, G2, G3,..., G6 arranged in parallel on a transparent TFT (thin film transistor) substrate 59, and is arranged in parallel at right angles to the row electrode group. There are a plurality of column electrodes S1, S2, S3,..., S6. A TFT 60 is provided at an intersection of each row electrode G and a column electrode S, a row electrode G is connected to a gate electrode of each TFT 60, a column electrode S is connected to a source electrode, and a pixel electrode is connected to a drain electrode. 61 are connected.
[0054]
A counter substrate 62 is disposed on the back side of the TFT substrate 59 so as to face the TFT substrate 59, and a counter electrode 63 having substantially the same area as the TFT substrate 59 is disposed on the counter substrate 62. Then, a liquid crystal is interposed between the pixel electrode 61 and the counter electrode 63.Provided, A pixel element 61 arranged in a matrix, a liquid crystal facing the pixel electrode 61 and a counter electrode 63 constitute a pixel matrix. A bias voltage is supplied to the counter electrode 63 by a power supply circuit 65 and a counter electrode driving circuit 64, and a pulse signal is repeatedly applied to the counter electrode 63 from a pulse generator 57 via a signal generating pen 55. . In this case, the counter electrode 63 is electrostatically coupled to the tip of the signal generating pen 55, and an induced voltage resulting from the pulse signal voltage of the pulse generator 57 is induced in the counter electrode 63.In the display panel 51, when the TFT 60 is turned on, a voltage is applied to the pixel electrodes 61, and the liquid crystal is driven by a voltage difference between a voltage applied to each pixel electrode 61 and a bias voltage applied to the counter electrode 63. Is done. Thus, a display is formed on the display panel 51. Then, during such display, a pulse signal from the pulse generator 57 is repeatedly applied to the counter electrode 63 via the signal generating pen 55. The pulse signal is a voltage at which the liquid crystal does not change even if the voltage difference between the pixel electrode 61 and the counter electrode 63 fluctuates when the pulse signal is applied to the counter electrode 63. Therefore, a normal display which is not affected by the pulse signal is formed on the display panel 51.
[0055]
The first signal detection electrode 65 and the second signal detection electrode 66 are provided at two different points adjacent to each other in the four corners of the counter electrode 63, and detect the pulse signal applied to the counter electrode 63, and perform the first phase comparison. The detection signal is sent to the detector 67 and the second phase comparator 68. The first and second phase comparators 67 and 68 have the same configuration as the first and second phase comparators 26 and 27 in FIG. 1 and are configured by the circuit shown in FIG. By the same operation, the first and second position information signals S1 and S2 are sent to the coordinate detection circuit 56. The coordinate detection circuit 56 detects the X and Y coordinates of the tip of the signal generating pen 55 on the display panel 51 based on the first and second position information signals.Note that the pulse signal is used to detect a phase difference based on the time of propagation through the counter electrode, and may be a voltage that can be detected by the first signal detection electrode 65 and the second signal detection electrode 66. If there is no problem. Therefore, even when a voltage that does not change the liquid crystal when the voltage applied to the liquid crystal is changed by the pulse signal is used as the pulse signal, the X and Y coordinates of the position where the tip of the signal generating pen 55 is in contact are accurately detected. be able to.
[0056]
The pulse signal applied to the counter electrode 63 is set to a voltage signal that does not affect the display by each picture element.Specifically, when a pulse signal is applied to the counter electrode 63, even if the voltage difference between the pixel electrode 61 and the counter electrode 63 fluctuates, the pulse signal has a voltage that does not change the liquid crystal.
[0057]
By inputting the coordinate signal detected by the coordinate detecting circuit 56 as a part of the display data to the display control circuit 54, the row electrode driving circuit 52 and the column electrode driving circuit are controlled by the display control circuit 54. The row electrode G and the column electrode S are driven by 53, and a point is displayed on the display panel 51 at the coordinates indicated by the signal generating pen 55. As a result, when the signal generating pen 55 slides on the display panel 51, pen input becomes possible.
[0058]
As described above, in the present embodiment, since the conductive film is formed by the counter electrode 63 of the active matrix type display panel 51, the position detecting device can be formed using the active matrix type display panel as it is. Therefore, according to the present embodiment, it is possible to provide a position detecting device in which the conductive film is integrated with the display panel simply and at low cost.
[0059]
In this embodiment, a position detection device integrated with a display panel as described above can be provided also in an embodiment in which the basic configuration shown in the second embodiment is combined with an active matrix type liquid crystal display device.
[0060]
When the signal generating pens 23 and 33 in the first and second embodiments apply a pulse signal to the conductive films 22 and 32, the conductive electrodes at the tips of the signal generating pens 23 and 33 directly contact the conductive films 22 and 32. Even in the configuration in which the voltage is applied, the tips of the signal generation pens 23 and 33 and the conductive films 22 and 32 are electrostatically coupled, and an induced voltage resulting from the signal voltage of the pulse signal is applied to the conductive films 22 and 32. May be induced and applied.
[0061]
In each of the above embodiments, a pulse signal is used as a basic signal, a pulse signal propagating on a conductive film is detected, and a phase difference from an output signal of a signal generator is detected by a phase comparator, or , The counter detects the propagation time to detect the coordinates, but the present invention is not limited to this.
[0062]
【The invention's effect】
As is clear from the above,The present inventionIn the position detecting device, a signal voltage from a signal generator is applied to the conductive film by designating an arbitrary point on the conductive film by a signal generating member. A propagation time until the signal voltage is detected is detected by a first signal detection electrode and a second signal detection electrode provided at two different points on the conductive film, and the signal generation is performed based on the propagation time. Determine the tip coordinates of the member. Thus, the coordinates of the tip of the signal generating member on the flat plate can be detected with high accuracy using a simple device including one conductive film covering the sliding range of the signal generating member, the signal generator and the signal generating member.
[0063]
Therefore, it is not necessary to arrange the row electrodes and the column electrodes in two layers on the position detection surface as in the conventional position detection device, and the detection accuracy is restricted by the arrangement pitch of the row electrodes and the column electrodes, and the row / column electrode two-layer structure is used. The detection error due to the difference in the distance between the electrodes is eliminated, and more accurate coordinate detection can be performed.
[0064]
Also,the aboveThe coordinate determination means comprises a phase comparator and a coordinate determination unit, and the phase shifter compares the phases of the first and second detection signals from the first and second signal detection electrodes with the output signal of the signal generator. To generate first and second position information signals representing the phase differenceAnd furthermore,The coordinate determination unit determines the tip coordinates of the signal generating member based on the first and second position information signals.By, The coordinate determination means can be easily and simply configured.
[0065]
Also,the aboveWhen the conductive electrode provided at the tip of the signal generating member contacts the conductive film, a signal voltage of a signal generator is applied to the conductive film.By doingThe signal voltage can be reliably detected by the first and second signal detection electrodes. Therefore, the tip coordinates of the signal generating member can be detected with higher accuracy.
[0066]
Also,the aboveThe signal generating member is electrostatically coupled to the conductive film, and induces an induced voltage on the conductive film due to the signal voltage.ByThe detection signal can be detected by the first and second signal detection electrodes without directly contacting the signal generation member on the conductive film. In this case, since the conductive film electrostatically coupled to the signal generating member is formed by one sheet, the detection accuracy of the X coordinate and the Y coordinate become the same, and Coordinates can be detected with high accuracy.
[0067]
Also,the aboveA first signal detection electrode and a second signal detection electrode provided on two sides adjacent to the conductive film detect a propagation time until a signal voltage propagating on the conductive film is detected.By doingThe tip coordinates of the signal generating member can be easily detected based on the propagation time.
[0068]
Also,the aboveConductive film is formed integrally with the display panel of the display deviceBy doingAn image can be displayed at the position indicated by the signal generating member based on the tip coordinates of the signal generating member determined by the coordinate determining means.
[0069]
Therefore, the member input by the signal generating member becomes possible as if writing on paper with a writing instrument.
[0070]
Also,the aboveThe conductive film is composed of the counter electrode of the active matrix type liquid crystal display panelBy doingThe position detection device can be formed using the active matrix type liquid crystal display panel as it is.
[0071]
Therefore, according to the present invention, it is possible to provide a position detecting device in which the above conductive film is easily integrated with the display panel at low cost.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a basic configuration of a position detecting device according to a first embodiment of the present invention.
FIG. 2 is a specific circuit diagram of a phase comparator in the position detection device shown in FIG.
FIG. 3 is a signal waveform diagram of each part in the position detection device shown in FIG.
FIG. 4 is a block diagram illustrating a configuration of a position detection device according to a second embodiment of the present invention.
FIG. 5 is a block diagram showing a configuration of a position detecting device according to a third embodiment of the present invention.
FIG. 6 is a block diagram illustrating a configuration of a position detecting device according to a fourth embodiment of the present invention.
FIG. 7 is a block diagram of a conventional position detecting device.
8 is a timing chart of a column electrode scanning signal and a row electrode scanning signal in the position detection device shown in FIG.
FIG. 9 is a block diagram of a conventional position detecting device different from FIG.
[Explanation of symbols]
21, 31, 41, 57 pulse generator
22, 32, 42 conductive film
23, 33, 43, 55 Signal generating pen
24 1st signal detection electrode
25 Second signal detection electrode
26, 46 First phase comparator
27, 47 Second phase comparator
28, 38, 48 Coordinate determination unit
34 X direction signal detection electrode
35 Y direction signal detection electrode
36 X direction counter
37 Y direction counter
44 1st signal detection electrode
45 2nd signal detection electrode
49 Display control unit
50, 51 Display panel
52 row electrode drive circuit
53 column electrode drive circuit
54 Display control circuit
67 1st position detection electrode
68 2nd position detection electrode
56 Coordinate detection circuit
58 Control unit
S1, S2 First and second position information signals
S3 coordinate signal

Claims (1)

A plurality of pixel electrodes arranged in a matrix, a counter electrode facing the plurality of pixel electrodes, and a liquid crystal provided between the plurality of pixel electrodes and the counter electrode form a pixel matrix. A position detection device integrated with a configured active matrix liquid crystal display panel,
A signal generator for generating a position detection signal;
A signal generating member having an electrode for outputting a position detection signal from the signal generator,
A conductive film having a uniform resistance component, an inductance component, and a capacitance component, and having a first signal detection electrode and a second signal detection electrode at two different points near the periphery;
A signal for position detection generated from the signal generator, and a signal from the signal generator applied to the conductive film in response to indicating an arbitrary point on the conductive film by the signal generating member. The coordinates of the point indicated by the signal generating member are determined based on the phase difference between the position detection signal and each detection signal detected by the first signal detection electrode and the second signal detection electrode, respectively. And a coordinate determining means,
The conductive film is a the counter electrode in the active matrix type liquid crystal display panel, the electrodes of the signal generating member, so as to induce an induced voltage to the conductive film and the capacitive coupling to the conductive film on the and which, furthermore, as the position detection signal generated from the signal generator does not affect the display of the liquid crystal display panel, the picture elements due to the position detection signal is applied to the conductive layer A position detecting device, wherein the liquid crystal is a pulse signal of a voltage that does not change due to a change in a voltage difference between an electrode and a counter electrode .

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