JPH10214156A - Device for detecting coordinate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the circuit construction of a display-integrated type tablet device. SOLUTION: The display detecting device 24 periodically switches a display control signal generated by a display control circuit 31 and a detection control signal generated by the arithmetic processing of a central processing circuit 37 by a switching circuit 42, applies it to a liquid crystal display device 28, and alternately executes a display operation and a coordinate detecting operation. At the time of a coordinate detecting operation, the X and Y coordinate electrodes of the liquid crystal display device 28 are successively scanned, and X and Y coordinate electrodes in the neighborhood of a desired instructing point are electrostatically connected with the instruction electrode of a pen member 34, and an instruction signal is derived. A central processing circuit 37 divides a lapse time clocked by a timer 38 by a unit time not more the time cycle of voltage impression on the X and Y coordinate electrodes, and detects the coordinates of the electrostatically connected coordinate electrodes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coordinate detecting device used as an input device of an electronic device such as a personal computer and a word processor.

[0002]

2. Description of the Related Art Conventionally, as an input device of a personal computer and a word processor, there is a coordinate detecting device called a tablet. The applicant of the present application has
No. 53726 proposes a display integrated tablet device. The display-integrated tablet device is a device that uses electrodes for display of a matrix display type liquid crystal display device as components for coordinate detection of a coordinate detection device.
For this reason, in the display-integrated tablet device, a display operation for displaying an image and a coordinate detection operation for detecting position coordinates in a visual display area of the device instructed by an operator of the device are time-divisionally performed. Alternately.

FIG. 22 is a block diagram schematically showing an electric structure of the display-integrated tablet device 1. As shown in FIG. In the following description, the display-integrated tablet device may be abbreviated as “tablet device”. The tablet device 1 includes a liquid crystal display device 3, a lighting device 4, a lighting control device 5, a switching circuit 7, a display control circuit 8, a detection control circuit 9, a detection pen 11, and an amplification circuit 18.

The liquid crystal display device 3 has a structure in which a liquid crystal layer is sandwiched between a pair of plate-like electrode members. Each of the electrode members is configured such that a plurality of strip-shaped coordinate electrodes are arranged in parallel with each other on one surface of a substrate having a light-transmitting property and facing one surface of the liquid crystal layer. When the pair of electrode members sandwich the liquid crystal layer, the coordinate electrodes on one surface of each substrate are arranged so as to be orthogonal to each other. Further, the liquid crystal display device 3 has, for each electrode member, an electrode control circuit for applying a predetermined voltage to each coordinate electrode on the substrate surface. When the liquid crystal display device is a transmissive liquid crystal display device, the lighting device 4 is installed on the other surface side of the substrate of one of the pair of electrode members. The lighting device 4 is turned on and off by a lighting control device 5. Thereby, the other surface of the substrate of one of the pair of electrode members of the liquid crystal display device 3 is used as a visual display area for visually displaying an image to the operator.

[0005] Each electrode control circuit of the liquid crystal display device 3 is connected to a display control circuit 8 and a detection control circuit 9 via a switching circuit 7.
Is electrically connected to The switching circuit 7 connects the display and detection control circuits 8 and 9 to the electrode control circuit alternately with time. The display control circuit 8 generates a display control signal for controlling each electrode control circuit so as to selectively scan each coordinate electrode in order to display a desired image in a visual display area of the liquid crystal display device 3. Then, it is given to each electrode control circuit via the switching circuit 7. The detection control circuit 9 is, specifically,
A timing generation circuit 13, a detection signal generation circuit 14,
It is configured to include X and Y coordinate detection circuits 15 and 16. Further, the detection control circuit 9 is accompanied by a detection pen 11 including an indication electrode, and this indication electrode is connected to X and Y coordinate detection circuits 15 and 16 via an amplification circuit 18.

When the detection control circuit 9 performs the coordinate detection operation, the operator brings the pointing electrode of the detection pen 11 close to a desired position in the visual display area of the liquid crystal display device 3 in advance. When the coordinate detection operation is started, the detection control circuit 9 continuously performs the X and Y coordinate detection operations. Since these coordinate detection operations are similar operations, the X coordinate detection operation will be described in detail,
The description of the Y coordinate detection operation is omitted. In the X-coordinate detection operation, first, an X-direction detection control signal is generated in response to a clock signal from the timing generation circuit 13, and the switching circuit 7
To one of the electrode control circuits. X
The direction detection control signal is applied to each coordinate electrode of one of the electrode members by one of the electrode control circuits.
A signal for controlling one of the electrode control circuits so that a predetermined detection voltage is sequentially applied at a predetermined time period. As a result, a detection voltage is sequentially applied to each coordinate electrode electrically connected to one of the electrode control circuits. In this case, when a detection voltage is applied to the coordinate electrode close to the indicator electrode, an induced voltage is induced at the indicator electrode. The X coordinate detection circuit 15
The electrode control circuit constantly counts whether or not the voltage is applied to which coordinate electrode of all the coordinate electrodes of one of the electrode members, and detects the detection voltage when an induced voltage is induced in the indicator electrode. Is detected as the X coordinate of the position designated by the operator. In the Y coordinate detection operation, the supply destination of the detection control signal is one of the other electrode control circuits, and the Y coordinate of the position designated by the operator is detected.

In the above-mentioned tablet device, the X and Y coordinates are the position coordinates of the coordinate electrodes that are electrostatically coupled to the pointing electrode. Therefore, the resolution for detecting the X and Y coordinates is determined by the arrangement of the coordinate electrodes on the electrode members of the liquid crystal display device 3. Therefore, in order to improve the resolution, it is necessary to change the liquid crystal display device 3 to a device having a structure in which the number of coordinate electrodes is larger than that of the original liquid crystal display device, and it is difficult to improve the resolution.

In the above-described tablet device, the switching circuit 7 and the detection control circuit 9 are often formed as a single circuit component as the tablet control circuit 10. The tablet control circuit 10 generates the detection control signal in the detection signal generation circuit 14 and the X and Y coordinate detection circuit 1
The operation of detecting the X and Y coordinates of 5, 16 is performed by a hardware-based processing operation using an electric circuit. For this reason, the tablet control circuit 10 is realized by a large-scale circuit in which the number of gates is 3000 to 4000 gates. When the circuit structure is complicated as described above, it is difficult to reduce the size, and the manufacturing cost of the tablet device increases.

Since the tablet control circuit 10 performs a processing operation like hardware, the circuit structure is the same as that of the liquid crystal display device 3.
And the specifications including the structure and behavior of the display control device 8. Therefore, when at least one of the specifications of the liquid crystal display device 3 and the display control device 8 is changed, the circuit structure of the entire tablet control circuit 10 needs to be changed. In such a tablet control circuit 10,
In order to improve the versatility of the control circuit 10, a plurality of circuits corresponding to the liquid crystal display device 3 and the display control device 8 having different specifications are provided in advance in the tablet control circuit 10, and the liquid crystal display device 3 and the display control device 8 are provided. There is a method for selecting a circuit to be used according to the specifications. In the tablet control circuit of this method, the number of gates of the control circuit 10 further increases as compared with the tablet control circuit 10 corresponding to the single specification of the liquid crystal display device 3 and the display control device 8 described above.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a coordinate detecting device having a tablet control circuit which can be used regardless of the specifications of a liquid crystal display device and a display control device.

[0011]

According to the present invention, a plurality of coordinate electrodes arranged along a coordinate axis and a plurality of coordinate electrodes arranged in the vicinity of the substrate are provided on a flat substrate surface on which predetermined coordinate axes are set. The first calculation processing includes: an indication electrode that is electrostatically or electromagnetically coupled to any one of the coordinate electrodes; and a selection control signal for sequentially selecting a specific coordinate electrode from among the plurality of coordinate electrodes. A selection control signal generating means, a selection means for sequentially selecting a specific coordinate electrode in a predetermined time period in response to the selection control signal, and an induction induced on the specific coordinate electrode or the indicator electrode. Voltage detecting means for detecting a voltage, timing means for measuring an elapsed time from when the selecting means starts selecting the specific coordinate electrode to when the voltage detecting means detects the induced voltage, and And a coordinate detecting means for detecting a coordinate point of a specific coordinate electrode electrostatically or electromagnetically coupled to the indicator electrode on the coordinate axis from the unit time predetermined based on the time period by a second arithmetic processing. A coordinate detection device characterized in that: According to the present invention, the coordinate detecting device is a so-called electrostatic coupling type or electromagnetic coupling type tablet device. The operator of the apparatus brings the pointing electrode of the pointing means close to a desired pointing point on the substrate. The coordinate detecting device detects whether or not an induced voltage is induced on the specific coordinate electrode or the indicator electrode by the voltage detecting device while causing the selecting device to sequentially select the specific coordinate electrode from the plurality of coordinate electrodes. Since the induced voltage is induced only when the specific coordinate electrode and the indicator electrode are electrostatically or electromagnetically coupled, when the induced voltage is not detected, the specific coordinate electrode and the indicator electrode selected at that time are electrostatically coupled. Or, it is considered that there is no electromagnetic coupling. Further, when the induced voltage is detected, it is considered that the specific coordinate electrode selected at that time and the indicator electrode are electrostatically or electromagnetically coupled, and the coordinate detecting means detects the specific coordinate electrode selected at that time. A coordinate point on a coordinate axis to represent a position is detected as a designated point. At this time, the operation of generating the selection control signal for controlling the selection means for selecting the specific coordinate electrode and the operation of detecting the coordinates of the coordinate point are performed by arithmetic processing. As a result, the control circuit required for these processing operations in the coordinate detection device of the related art can be realized by a virtual circuit realized by the processing operation of the central processing circuit (CPU), for example. Therefore, 3000 gates ~
The control circuit for the coordinate detection operation, which was a large-scale circuit with 4000 gates, can be deleted from the coordinate detection device. Thus, the circuit structure of the entire coordinate detecting device can be simplified. In the above-described coordinate detection operation, the above-described elapsed time is measured, and the coordinate detection operation is performed by an arithmetic process using the elapsed time and the above-described unit time. At this time, by setting the unit time to a value smaller than the above-described time period, the apparent resolution of the coordinate detection device can be improved. This also makes it possible to improve the accuracy of the obtained coordinate values as compared with the coordinate detection device of the related art.

Further, according to the present invention, the selection means generates a scanning signal for scanning the specific coordinate electrode based on the selection control signal generated by the selection control signal generation means, and supplies the scanning signal to each of the coordinate electrodes. It is characterized by giving. According to the present invention, the above-described coordinate detection device is an electrostatic coupling type tablet device, and charges the specific coordinate electrode by scanning all the coordinate electrodes with a scanning signal. by this,
When the specific coordinate electrode and the indicator electrode are electrostatically coupled, an induced voltage is induced in the indicator electrode. In this case, the selection control signal for selecting the specific coordinate electrode is likely to have a complicated signal structure, and according to the conventional technique, it is easy to form a large-scale circuit with several thousand gates. At this time, the circuit structure of the coordinate detection device can be simplified by performing the operation of generating the selection control signal and the operation of detecting the coordinates of the coordinate points as described above.

[0013] The present invention is characterized in that the unit time can be changed. According to the present invention, the unit time used in the coordinate detecting operation of the coordinate detecting device can be changed. This makes it possible to arbitrarily change the apparent resolution of the coordinate detection device.

Also, in the present invention, the first and second arithmetic processings include a plurality of processes according to a configuration of the number of input terminals of the voltage detecting means and a signal transmission / reception speed, and an arrangement of a plurality of the coordinate electrodes. Then, any one of the plurality of processes is selected and executed. According to the present invention,
The first and second calculation processes of the coordinate detection device include the above-described configuration of the selection unit and a plurality of processes corresponding to the arrangement of the plurality of coordinate electrodes. When the coordinate detection device detects the above-described coordinate points, the first and second arithmetic processings are executed by selecting one of the processings corresponding to the selection means and the arrangement of the coordinate electrodes used at that time. Thus, the coordinate detection device does not need to change the other structure of the coordinate detection device when the configuration of the selection unit and the arrangement of the coordinate electrodes are changed. Therefore, it is possible to easily change the design of the selecting means and the coordinate electrode as compared with the coordinate detection device of the related art. Further, since the selection means and the arrangement of the coordinate electrodes to be used can be arbitrarily selected, the versatility of the coordinate detection device can be improved. Further, since the above-mentioned plurality of processes are arithmetic processes, specifically,
For example, this is realized by preparing a plurality of programs to be executed by a central processing circuit (CPU). Therefore, even if the number of processes prepared in advance is increased, the number of gates of the circuit does not increase. Therefore, the versatility of the coordinate calculation device can be improved without increasing the circuit scale.

Further, in the present invention, the coordinate electrode is a strip-shaped electrode, the substrate includes two substrates, and a panel member including the coordinate electrodes and having a rectangular coordinate system is formed. One surface includes two substrates on each of which the coordinate electrodes are arranged in parallel with each other, at predetermined intervals so that the longitudinal directions of the coordinate electrodes of each substrate are orthogonal, and one surface faces each other. A display medium that is arranged and has a display characteristic that changes according to whether or not a pair of opposed coordinate electrodes is scanned is a panel member sandwiched between two substrates, and the coordinate detection device includes: A display control signal generating means for generating a display control signal for selectively changing a display characteristic of a display medium interposed between the opposed coordinate electrodes, and a display control signal generated by the display control signal generating means. The selection control signal Switching means for alternately switching the selection control signal generated by the generation means with a switching time period determined by a predetermined cycle calculation process and providing the switching control signal to the selection means, wherein the selection means comprises a display control signal Is provided, a scan signal for scanning the opposed coordinate electrodes is generated based on a display control signal, and the scan signal is provided to each coordinate electrode. According to the present invention, the above-described coordinate detection device is a so-called display-integrated tablet device, and the coordinate electrode also serves as a part of a panel member for display. In this panel member, a pixel is formed at each intersection position where the coordinate electrode is orthogonal at the twisted position. When the panel member is used for the display operation, the selecting means selectively scans all coordinate electrodes in response to the display control signal,
The display characteristics of the display medium between the opposing coordinate electrodes are selectively changed for each pixel. By combining the pixels that have changed in display characteristics and the pixels that do not change as described above, an image can be displayed as the entire panel member. In such a coordinate detection device, the display control signal and the detection control signal are alternately and periodically switched by the switching means and provided to the selection means, and the display operation and the coordinate detection operation are periodically performed in a time-division manner.
In such a display-integrated tablet device, the above-described selection means often accompanies the panel member from the beginning,
In many cases, the above-described selection control signal generation means, indicator electrode, timekeeping means, and coordinate calculation means are added later.
At this time, by performing the signal generation operation and the coordinate detection operation by arithmetic processing, the circuit scale of the means to be added later can be reduced. Further, by adopting a structure in which an induced voltage is induced in the indicator electrode as in claim 2, the selecting means added to the panel member of the display device can be used as it is.

In the present invention, the switching time period can be changed according to the display control signal generated by the display signal generating means, the number of input terminals of the selecting means, the signal transfer speed, and the like. It is characterized by the following. According to the present invention, the switching time period of the switching means can be changed according to the display control signal and the configuration of the selecting means. Therefore, the coordinate detecting device can arbitrarily select the selection means and the arrangement of the coordinate electrodes to be used, so that the versatility of the coordinate detecting device can be improved. For example, when the specification of the display control means is changed and the display control signal is changed, the coordinate detection device can be changed accordingly. Further, since this switching time period is determined by the arithmetic processing of the switching control means, it can be changed without changing the circuit structure of the coordinate detecting device. Therefore, it is possible to easily change the design of the coordinate detecting device. Further, since the switching time period is determined by the arithmetic processing, it is not necessary to provide a plurality of electric circuits in advance as in the conventional coordinate detection device. Therefore, the circuit scale of the coordinate detecting device can be reduced as compared with the conventional coordinate detecting device.

Further, the present invention is characterized in that a single integrated circuit is formed by the selection control signal generating means, the coordinate detecting means, the switching means, and the timing means. According to the present invention, the above four means are integrated to form an integrated circuit. As described in the first aspect, the coordinate detecting device of the present invention can be easily integrated because a large-scale circuit whose number of gates is on the order of thousands is eliminated. Therefore, the number of parts of the entire coordinate detecting device is reduced, and the structure of the coordinate detecting device can be simplified.

Further, the present invention is characterized in that a single integrated circuit is formed by the selection control signal generating means, the coordinate detecting means, and the timing means. According to the present invention, an integrated circuit is formed by integrating the above three means. As described in the first aspect, the coordinate detecting device of the present invention can be easily integrated because a large-scale circuit whose number of gates is on the order of thousands is eliminated. Therefore, the number of parts of the entire coordinate detecting device is reduced, and the structure of the coordinate detecting device can be simplified.
Further, this integrated circuit does not include a switching means.
The switching means may need to change the circuit structure itself according to the structure of the panel member and the selection means and the signal configuration of the display control signal. Therefore, by not incorporating the switching means in the integrated circuit, the structure of the coordinate detecting device can be easily changed without changing the structure of the integrated circuit when the above-described structure and signal configuration are changed. Furthermore, when the switching means is not built in the integrated circuit, the number of terminals of the integrated circuit can be reduced as compared with the case where the switching means is built in the integrated circuit.

Further, the present invention further includes signal generation control means for controlling the selection control signal generation means so as to generate the selection control signal, wherein the signal generation control means, the selection control signal generation means, and the coordinate detection A single arithmetic circuit is formed by the means. According to the present invention, in the selection control signal generation means, the timing of signal generation is controlled by the signal generation control means. The signal generation control means, the selection control signal generation means, and the coordinate detection means form a single arithmetic circuit. Thereby, the circuit structure of the coordinate detecting device can be simplified. Therefore, when a plurality of circuits are integrated as in claims 7 and 8, it can be easily integrated.

Further, the present invention is characterized in that a single arithmetic circuit is formed by the selection control signal generating means and the coordinate detecting means. According to the present invention, as described above, the selection control signal generating means and the coordinate detecting means form a single arithmetic circuit. Thereby, the circuit structure of the coordinate detecting device can be simplified. Therefore, when a circuit is integrated as in claims 7 and 8,
It can be easily integrated. Further, as compared with the coordinate detecting device of the ninth aspect, the signal generation control means is provided separately from the arithmetic circuit, so that the load on the arithmetic circuit can be reduced. Further, when the signal generation control means is configured to form an operation circuit separate from the above-described operation circuit, the load on the operation circuit of the signal generation control means is reduced as compared with the operation circuit according to claim 9. A decrease in the throughput of the means can be prevented.

[0021]

FIG. 1 is a block diagram showing an electric configuration of an electronic device 21 including a coordinate detecting device according to a first embodiment of the present invention. The electronic device 21 includes a host device 23 and a display detection device 24, and the display detection device 24
Is used also as a display device of the host device 23 and a coordinate detection device.

The host device 23 is realized by, for example, a personal computer and a word processor. A central processing circuit 26 is provided in the host device 23. This central processing circuit 26 includes the signal generation control means described in the claims.

The display detecting device 24 includes the liquid crystal display device 2
8, a lighting device 29, a display control circuit 31, and a tablet control circuit 32. The liquid crystal display device 28 is “LCD” in the drawing.

The liquid crystal display device 28 is a transmission type simple matrix type liquid crystal display device and has a flat two-dimensional planar display detection area. The illumination device 29 is provided to increase the luminance of the display detection area of the liquid crystal display device 28, and is installed on the opposite side of the liquid crystal display device 28 from the display detection region. The liquid crystal display device 28 is controlled by a display control signal generated by a display control circuit 31 when the display detection device 24 operates as a display device. When the display detecting device 24 operates as a coordinate detecting device, the display detecting device 24 is controlled by a detection control signal generated by the central processing circuit 37 in the tablet control circuit 32.

The display control circuit 31 and the central processing circuit 37 are connected to the interface circuit 41 of the tablet control circuit 32.
Is connected to the liquid crystal display device 28 via a switching circuit 42 therein. The switching circuit 42 connects one of the circuits 31 and 37 to the liquid crystal display device 28, and alternately switches the connection in a time-division manner. As a result, the display control signal and the detection control signal are alternately switched from the switching circuit 42 to the liquid crystal display device 28.
Given to. The detection control signal corresponds to a selection control signal in the claims.

Specifically, the display control circuit 31 is supplied with a display image signal representing an image to be visually displayed on the display detection area of the liquid crystal display device 28 from the host device 23. The display control circuit 31 generates the above-described display control signal for controlling the liquid crystal display device 28 so as to visually display the image represented by the display image signal based on the given display image signal, and give.

The tablet control circuit 32 includes a pen member 34, a determination circuit 35, an input port 36, a central processing circuit 37, a timer 38, and a memory 3 in addition to the interface circuit 41.
9, 40 and an interface circuit 44. In the drawing, the interface circuit is referred to as “I / F”.

The pen member 34 is a rod-shaped member that can move in the vicinity of the display detection area of the liquid crystal display device 28, and is used by an operator of the apparatus to specify an arbitrary designated point in the display detection area. In the coordinate detection operation of the display detection device 24, a substrate member described later of the liquid crystal display device 28 and an indicator electrode provided at the tip of the pen member 34 are combined to form an electrostatic induction type tablet device. In the electrostatic induction type tablet device, the indicator electrode of the pen member 34 is brought into contact with or close to the surface of the substrate member in the display detection area, and the induced voltage induced by the electrostatic coupling between the coordinate electrode included in the substrate member and the indicator electrode. Is used to indicate an arbitrary designated point in the display detection area. Details of this instruction operation will be described later.

A sensor circuit including an indicator electrode is provided in the pen member 34, and represents a contact signal indicating that the pen member 34 has contacted the surface of the substrate member and a voltage value of an induced voltage induced on the indicator electrode. A voltage signal is generated, and the judgment circuit 3
5 is derived. In addition to the above-described instruction operation, a button for instructing execution of another function of the electronic device 21 may be added to the pen member 34 in some cases. When the operator of the electronic device 21 operates this button, an operation signal corresponding to the operated button is supplied to other components of the electronic device 21 via the determination circuit 35, and another function designated by the button is performed. You.

The judgment circuit 35 amplifies the contact signal, the voltage signal, and the operation signal because the signal levels of the contact signal, the voltage signal, and the operation signal given from the pen member 34 are very small. Next, the voltage signal is subjected to waveform shaping, and the voltage signal after waveform shaping is subjected to level discrimination at a discrimination level corresponding to a predetermined voltage value of the induced voltage. When the signal level of the voltage signal is equal to or higher than the discrimination level, an induced voltage equal to or higher than a predetermined voltage value is induced in the indicator electrode. An instruction signal is output. When the voltage signal is less than the discrimination level, it is determined that the coordinate electrode and the indicator electrode are not electrostatically coupled, and no signal is output or a signal indicating that is output. The amplified contact signal, operation signal, and instruction signal are supplied from the determination circuit 35 to the central processing circuit 37 via the input port 36. The instruction signal is also supplied to the timer 38.

As will be described later, the timer 38 measures the elapsed time from when the coordinate detection operation is started to when the instruction signal is given. The timing operation and time setting of the timer 38 are controlled by the central processing circuit 37. Further, a latch circuit is provided in the timer 38, and when an instruction signal is given from the determination circuit 35, the memory 39 for holding the elapsed time measured by the timer 38 is realized by, for example, a read-only memory, The processing circuit 37 stores an arithmetic processing program for performing various processing operations. The various processing operations include a coordinate detection operation and a command processing operation described later. The memory 39 also stores parameters having fixed values among the parameters of these programs. The memory 40 is realized by, for example, a random access memory, and temporarily stores data and signals when the central processing unit 37 executes a program for a coordinate detection operation and a command processing operation described later.

The above-described interface circuit 41 includes a display control circuit 31, a liquid crystal display device 28 and a lighting device 29,
This is a circuit for exchanging signals and data with the tablet control circuit 32. The interface circuit 41 includes a register group 43 for storing data and signals to be transmitted and received, in addition to the switching circuit 42 described above.
The detailed structures of the switching circuit 42 and the register group 43 will be described later. Further, the interface circuit 44 includes the host device 2
3 and a tablet control circuit 32 for transmitting and receiving signals and data. Interface circuit 4
Reference numerals 1 and 44 may be individual circuits, or may be a configuration realized by a single interface circuit.

The central processing circuit 37 includes a signal generator 48, a coordinate detector 49, and a switching controller 50. These units 48 to 50 are virtual circuits realized by the arithmetic processing of the central processing circuit 37. The central processing circuit 37 performs various operations based on the contents stored in the memories 39 and 40 and the register group 43, the elapsed time measured by the timer 38, and the signals and data transmitted and received by the interface circuits 41 and 44. Signal generator 48 and coordinate detector 49
, A coordinate detection operation described later is performed. In this coordinate detection operation, the signal generation section 48 of the central processing circuit 37 generates the above-described detection control signal. Further, the switching control unit 50 of the central processing circuit 37 controls the switching circuit 42 so that the detection control signal generated by the signal generation unit 48 and the display control circuit 31
Is applied to the liquid crystal display device 28.

The tablet control circuit 32 includes an input port 36, a central processing circuit 37, a timer 38,
Memories 39, 40 and interface circuits 41, 44
Is preferably formed as a single integrated circuit 46. Thus, the number of components of the tablet control circuit 32 is reduced, so that the manufacturing process of the electronic device 21 is simplified, and the manufacturing cost can be reduced. Also,
The determination circuit 35 determines that the structure of the pen member 34 is
When the structure changes in response to the structure of FIG. 8, the structure may change in conjunction therewith, and the determination circuit 35 is realized by an analog circuit. Therefore, it is preferable that the determination circuit 35 is not included in the integrated circuit 46. This allows the integrated circuit 46
Can be further reduced in size than an integrated circuit incorporating the decision circuit 35. Further, when there is a design change related to the determination circuit 35, the design change of the integrated circuit 46 is not performed, so that the design change of the tablet control circuit 32 can be easily performed.

FIGS. 2 and 3 are plan views showing the detailed structure of the liquid crystal display device 28. FIG. There are two types of structures of the liquid crystal display device 28, a single panel structure shown in FIG. 2 and a dual panel structure shown in FIG. 3. Used for the electronic device 21.

The liquid crystal display device 51 having a single panel structure
Is a panel member 52 and an X and Y coordinate electrode control circuit 5
3 and 54. The panel member 52 includes a pair of light-transmitting flat plate-shaped substrate members and a liquid crystal layer. In the pair of substrate members, a plurality of strip-shaped X and Y coordinate electrodes 56 and 57 are formed on one surface of each of two light-transmitting flat substrates, and further, one surface of the substrate and X and Y It has a structure in which an alignment film covering the Y coordinate electrode is formed. The arrangement of the X and Y coordinate electrodes 56 and 57 is such that the longitudinal direction of each of the strip-shaped X and Y coordinate electrodes 56 and 57 is parallel to each other and a predetermined interval along a direction orthogonal to the longitudinal direction. Is an array that can be arranged with. The Y coordinate axis and the X coordinate axis of the XY orthogonal coordinate system set on the panel member 52 are parallel to the longitudinal directions of the X and Y coordinate electrodes 56 and 57, respectively, and are represented by arrows Y and X, respectively. In the drawing, the X and Y coordinate electrodes 56, 57 represent only two of the substrate edges,
Other X and Y coordinate electrodes 56 and 57 are omitted. The liquid crystal layer opposes the pair of substrate members with one surface of the substrate on which the X and Y coordinate electrodes are respectively formed at a predetermined interval, and the longitudinal direction of the X and Y coordinate electrodes is one surface of the substrate member. Are formed so as to be orthogonal to each other at the twisted position when viewed from the normal direction, and to seal the periphery of the gap between the pair of substrate members and to enclose a liquid crystal material in the gap.

In the panel member 52 thus formed, the other surface of one of the pair of substrate members is used as a display detection area of the liquid crystal display device 28. The above-described lighting device 29 is installed close to the other surface side of the substrate of one of the pair of substrate members. When viewed from the normal direction of one surface of the substrate of the panel member 52, pixels of the display detection area are formed at intersections where the X and Y coordinate electrodes 56 and 57 intersect and face each other. The pixels are arranged in a matrix in the display detection area, and form rows and columns parallel to the X and Y directions, respectively. The position coordinates of an arbitrary designated point in the display detection area are as described above in XY.
Expressed in a rectangular coordinate system.

The X coordinate electrode control circuit 53 is installed, for example, adjacent to an edge of the panel member 52 parallel to the X direction, and is electrically connected to one end of each X coordinate electrode 56 individually. . The Y coordinate electrode control circuit 53 is installed, for example, adjacent to an edge of the panel member 52 parallel to the Y direction.
Each Y coordinate electrode 57 is individually electrically connected to one end. The X and Y coordinate electrode control circuits 53 and 54 individually apply a predetermined display voltage or detection voltage to the X and Y coordinate electrodes 56 and 57, respectively. X and Y
The coordinate electrode control circuits 53 and 54 correspond to the selecting means in the claims.

Of the X and Y coordinate electrodes 56 and 57, the specific coordinate electrode described above is selected according to the display control signal and the detection control signal. The display and detection control signals are each a set of a plurality of types of individual signals, as will be described later. Are included. In the drawing, each signal is referred to as “SCL
K "," DATA "," LP "," M "," FRM ".

Each of the above-mentioned individual signals is transmitted through a different signal line.
54 individually. Specifically, the X coordinate electrode control circuit 53 is provided with a data signal, a clock signal, a latch pulse signal, and a modulation signal.
A modulation signal,
A latch pulse signal and a frame signal are provided.

The Y coordinate electrode control circuit 5 of the liquid crystal display device 28
Reference numeral 4 is controlled by a frame signal and a latch pulse signal, and determines a specific coordinate electrode to which a detection voltage or a display voltage is to be applied. For example, when a frame signal is given, the Y coordinate electrode control circuit 54 selects a coordinate electrode arranged at a position where the Y coordinate is 0 as a specific coordinate electrode. After the frame signal is applied, each time a pulse of the latch pulse signal is input, the Y coordinate electrode control circuit 54
The coordinate electrodes arranged adjacent to the direction of increasing the Y coordinate of the specific coordinate electrode before the pulse input are sequentially changed so as to be the next specific coordinate electrode.

Further, an X and Y coordinate electrode control circuit 5
Power for operating the circuits 53 and 54 is supplied to the power supplies 3 and 54 from a power supply source 59. Further, the X and Y coordinate electrode control circuits 53 and 54 receive a density adjustment signal from the density adjustment circuit 60. The density adjusting circuit 60 adjusts the density of the white pixel and the black pixel and the density difference between the two pixels in the display detection area of the liquid crystal display device 51.

A liquid crystal display device 61 having a dual panel structure
Has a structure in which two liquid crystal display devices having a single panel structure are combined. The liquid crystal display device 61 is, specifically,
First and second panel members 62 and 63, first and second panel members
It has X coordinate electrode control circuits 64 and 65 and first and second Y coordinate electrode control circuits 66 and 67. The first and second panel members 62 and 63 have the same structure, and are different from the panel member 52 of the liquid crystal display device 51 in that the width of the substrate in the Y direction, the length of the X coordinate electrode 56 in the longitudinal direction, and Y The difference is that the number of coordinate electrodes 57 is half each, and the remaining structure is the same as the panel member 52. The first and second X coordinate electrode control circuits 64 and 65 and the first and second Y coordinate electrode control circuits 66 and 67 compare the X and Y coordinate electrode control circuits 53 and 54 with the X and Y coordinate electrodes to be controlled. Are different from the X and Y coordinate electrodes 56 and 57 of the liquid crystal display device 51 having a single panel structure in the structure and behavior of the portions related to the difference, and the remaining structure and behavior are the same.

FIG. 4 is a block diagram showing a specific structure of the switching circuit 42. The switching circuit 42 is configured to include the same number of switching elements as the individual signals included in the display and detection control signals, and the switching circuit 42 of the present embodiment is configured to include five switching elements 71 to 75.

The switching element 71 has two individual signal input terminals 71A and 71B, a switching signal input terminal 71S, and a single output terminal 71O. The display control circuit 31 and the central processing circuit 37 supply data signals of display and detection control signals to the switching element 71 in parallel from the individual signal input terminals 71A and 71B. The switching control unit 50 of the central processing circuit 37 selects one of the display and detection control signals to be given to the liquid crystal display device 28 from the display and detection control signals at predetermined time periods described later. Specifically, the switching control unit 50 selects a display control signal when performing a display operation with the display detection device 24, and selects a detection control signal when performing a coordinate detection operation with the display detection device 24. Switching control unit 50
Generates the above-described switching control signal for controlling the switching circuit 42 so as to supply one of the control signals to the liquid crystal display device 28, and generates the switching signal input terminal 7 of the switching element 71.
1S to the switching element 71.

When a switching control signal is applied, switching element 71 outputs an individual signal input terminal, to which the data signal of one of the control signals represented by the switching control signal is supplied, from among individual signal input terminals 71A and 71B. The contact is switched so as to be connected to the terminal 71O. As a result, the data signal supplied to the individual signal input terminal is led out of the switching element 71 and applied to the X coordinate electrode control circuits 53;

The structure of the switching elements 72 to 75 is
Equal to 1. The behavior of switching element 72 is different only in that the individual signal applied to individual signal input terminals 72A and 72B is a clock signal, and the remaining behavior is that of switching element 71.
Is equal to The behavior of the switching element 73 is different only in that the individual signals supplied to the individual signal input terminals 73A and 73B are latch pulse signals.
Equal to 1. The behavior of the switching element 74 is different only in that the individual signals supplied to the individual signal input terminals 74A and 74B are modulation signals, and the remaining behavior is the same as that of the switching element 71. The behavior of the switching element 75 is different only in that the individual signals applied to the individual signal input terminals 75A and 75B are frame signals, and the remaining behavior is the same as that of the switching element 71. A description of parts having the same structure and behavior is omitted.

Each of these switching elements 71 to 75 may be individually operated by receiving an individual switching control signal.
Further, since the change timings of the individual signal input terminals 71A to 75A and 71B to 75B switched by the switching elements 71 to 75 are all the same, the switching control unit 50 generates a single switching control signal, and May be applied to the switching signal input terminals 71S-75S of the switching elements 71-75 to control the switching elements 71-75. As a result, the switching control signal can be realized by a single signal, so that the signal generation operation in the switching control unit 50 can be simplified as compared with the case where the switching control signals are individually generated.

The detailed structure of the register group 43 in the interface circuit 41 will be described below with reference to FIGS.

The register group 43 includes a data register 9
1, a control register 92, a command register 93, a status register 94, a flag register 95, and a model register 96. It also includes an X and Y scan line number register and a scan line number register. For example, data register 91 is implemented by a 16-bit register having 16 store cells. Also, for example,
Each of the registers 92 to 96 is realized by an 8-bit register having eight store cells. In the drawing, each store cell is hereinafter represented by a rectangular area. The bits stored in the 1st to 16th store cells counted from the right end in the drawing among the respective store cells of the registers 91 to 96 are:
These are referred to as bits b0 to b15, respectively. These bits b
In the drawing, 0 to b15 are assigned as symbols in a rectangular area representing a store cell in which the bit is to be stored.

FIG. 5 is a schematic diagram showing a specific structure of the data register 91. The data register 91 divides the data signal of one of the display and detection control signals, which is switched to the switching circuit 42, for each predetermined number of bits, and sequentially stores them. This data signal indicates the presence or absence of display and detection voltage application to each X coordinate electrode 56 of the liquid crystal display device 28. The predetermined number of bits is determined by the data bit length. The data bit length is X
The number of bits that can be transmitted and received in parallel by the coordinate electrode control circuits 53; 64, 65 is determined by, for example, the number of data signal input terminals of the X coordinate electrode control circuits 53; 64, 65.

All bits b0 to b1 of data register 91
Of 5, the number of bits used for storing data is the same as the data bit length, and the remaining bits are not used. When the liquid crystal display device 28 is a liquid crystal display device 61 having a dual panel structure, the data signal is divided and applied to the first and second X coordinate electrode control circuits 64 and 65 in parallel. At this time, the data register stores
The bits of the data signal applied to the coordinate electrode control circuit 64 are sequentially stored from bit b0, and the bits of the data signal applied to the second X coordinate electrode control circuit 65 are sequentially stored from bit b8.

Therefore, for example, when a 4-bit single panel liquid crystal display device having a data bit length of 4 bits is used, the transmission and reception of the data signal are performed using bits b0 to b
3 are used, and the remaining bits b4 to b15 are not used. When an 8-bit single panel liquid crystal display device having a data bit length of 8 bits is used, bits b0 to b7 are used for transmitting and receiving data signals, and the remaining bits b8 to b15 are not used. Furthermore, when a liquid crystal display device having a 4-bit dual panel structure is used,
To transmit and receive the data signal, bits b0 to b4, b8 to b1
1 is used, and the remaining bits b4 to b7 and b12 to 15
Is not used. When an 8-bit dual panel liquid crystal display device is used, all bits b0 to b15 are used for data signal transmission and reception. Specifically, when connecting the data register 91 and the interface circuit 41, the output terminal from which the bit to be used is output is connected to the input / output terminal of the interface circuit, and the remaining output terminals are not connected. The data signals to be supplied to the X coordinate electrode control circuits 53; 64, 65 are divided and stored so as to be outputted only from the connected output terminals.

FIG. 6 is a schematic diagram showing a specific structure of the control register 92 and signals represented by bits b0 to b7. The content of the digital signal stored in each bit b0 to b7 of the control register 92 differs between the display operation and the coordinate detection operation. Switching of the storage contents of the control register 92 is performed by first setting the value of the bit b5 of the control register 92 to 0.
, The output control signal to the lighting device 29 is controlled so that the lighting device 29 is turned off. further,
The operation is switched by reading the frame signal of the display control signal represented by bit b2.

FIG. 6A shows each bit b0 during the display operation.
FIG. 6B shows the correspondence between the bits b0 to b7 and the signal during the coordinate detection operation.

At the time of display operation, bit b0 represents a clock signal of a display control signal. Bit b1 represents a latch pulse signal of the display control signal. Bit b2 represents the frame signal of the display control signal. Bit b3 represents the modulation signal of the display control signal. Bit b5 represents a lighting control signal for controlling lighting and extinguishing of lighting device 29. Bit b6 represents a switching control signal for controlling switching circuit 42. Bits b4 and b7 are unused and have no signal to represent.

At the time of the coordinate detection operation, the bit b0 represents the clock signal of the detection control signal. Bit b1 represents a latch pulse signal of the detection control signal. Bit b2 represents the frame signal of the detection control signal. Bit b3 represents the modulation signal of the detection control signal. Bit b5 is
This represents the aforementioned operation signal from the pen member 34. Bit b6
Represents the above-mentioned instruction signal from the determination circuit 35. Bits b4 and b7 are unused and have no signal to represent.

FIG. 7 is a schematic diagram showing a specific structure of the command register 93 and signals represented by bits b0 to b7. The command register 93 stores the central processing circuit 3 in response to an instruction from the host device 23 and the display control circuit 31.
7 and the central processing circuit 37
, A command signal independently generated for the coordinate detecting operation is written. The command signal is a signal indicating a processing operation to be performed by the central processing circuit 37, and includes a command code and command data. The command code represents a processing operation to be performed by the central processing circuit 37, and a plurality of types are prepared. For example, the command code is a 6-bit digital signal, and can represent up to 32 types of control operations. The command data represents information required when the central processing circuit 37 performs the processing operation represented by the command code, for example, a parameter value. The control register 93 first stores a command code, and after reading out the stored command code, stores the command data.

FIG. 7A shows the correspondence between the bits b0 to b7 and the digital signal when the command code is stored. Bit b7 indicates whether the digital signal currently stored in control register 93 is either a command code or command data. For example, bit b7
It is assumed that the digital signal stored when the value is 1 is a command code, and that when the value is 0 is command data. When the command code is stored, bit b1
To b6 represent command codes. Bit b0 is an option of the command code, and represents the command data when the command data for the command code is a 1-bit digital signal.

FIG. 7B shows the correspondence between the bits b0 to b7 and the digital signal when the command data is stored. When command data is stored, bit b
0 to b6 represent command data. When the command data is a digital signal of 2 bits or more, the first bit of the command data is stored in the bit b0 when the command code is stored. Store the remaining bits up to the last bit. At this time, bit b
The value of 7 is set to 0. Further, when the original command data is a digital signal of 9 bits or more, the remaining bits are divided into 7 bits, and the command register 9
Every time the storage contents of No. 3 are read, they are sequentially written and stored.

FIG. 8 is a schematic diagram showing the specific structure of the status register 94 and the signals represented by the bits b0 to b7. The status register 94 includes the display detection device 24.
, And the operation results of the coordinate detection operation and the command processing operation performed by the central processing circuit 37. Bit b0 indicates that the digital signal currently stored in command register 93 is command data. Bit b1 indicates that the command processing operation performed by the central processing circuit 37 has been abnormally terminated. Bit b4 indicates that the command processing operation performed by the central processing circuit 37 has been completed normally. The bit b5 indicates that there is no designated point in the display detection area designated by the pen member 34. Bit b6 indicates that the coordinate detection operation performed by the central processing circuit 37 has been completed normally. Bit b7 indicates that the signal stored in status register 94 is a status indicating the operation state and operation result of central processing circuit 37, and the value is fixed to 1. Bits b2, b3
Is unused and has no signal to represent.

FIG. 9 is a schematic diagram showing the specific structure of the flag register 95 and the flags represented by the bits b0 to b7. Each bit b0 to b7 of the flag register represents the value of a flag used for the processing operation in the central processing circuit 37. Bit b0 represents a coordinate detection flag indicating whether or not the coordinate detection operation is performed. Bit b1 represents a continuous detection flag indicating whether to continuously execute the coordinate detection operation. Bit b2 represents a scanning method flag for selecting a scanning method in a coordinate detection operation described later. Bit b3 is
An indication point flag indicating the presence or absence of an indication point is shown. Bit b5
Represents a panel select flag indicating a panel member of the liquid crystal display device 28 to be scanned in the coordinate detection operation described later.
Bit b6 represents a lighting control flag for controlling lighting and extinguishing of lighting device 29. The bit b7 indicates a flag indicating whether or not the interrupt processing of the central processing circuit 37 is performed. Bit b4 is unused and has no flags to represent.

FIG. 10 is a schematic diagram showing a specific structure of the model register 96 and a structure name of the liquid crystal display device represented by each bit b0 to b7. The bit b0 is set in the liquid crystal display device 2
Reference numeral 8 indicates whether or not the liquid crystal display device has an active matrix structure, for example, using a TFT (thin layer transistor). The bit b1 indicates whether the liquid crystal display device 28 is a liquid crystal display device 51 having a single panel structure. The bit b2 indicates whether the liquid crystal display device 28 is a liquid crystal display device 61 having a dual panel structure. The bit b3 represents the data bit length of the X coordinate electrode control circuit 53; 64, 65. Specifically, when the value is 0, it indicates that the data bit length is 4 bits. Indicates that the length is 8 bits. The bit b4 indicates whether the data bit length is 16 bits. The bit b7 indicates whether the liquid crystal display device 28 is a device having another structure other than the above structure. Bits b5 and b6 are unused and have no structure to represent.

The display detection device 24 is a so-called display-integrated tablet device, and uses the liquid crystal display device 28 alternately for a display operation and a coordinate detection operation.

When the liquid crystal display device 28 is used for a display operation, the X and Y coordinate electrode control circuits 53, 54;
The display control signal from the display control circuit 31 is supplied to the display control circuit 67 through the interface circuit 41.

The Y coordinate electrode control circuit 54;
A predetermined display scanning voltage is sequentially applied to each Y coordinate electrode 57 in accordance with the frame signal and the latch pulse signal. The X coordinate electrode control circuits 53; 64, 65 are synchronized with the Y coordinate electrode control circuits 54; 66, 67 by a clock signal synchronized with the latch pulse signal, and all the X coordinate electrodes 56
Then, a predetermined display data voltage is applied selectively based on the data signal according to the column to which the display scanning voltage is applied. As a result, the voltage between the Y-coordinate electrode 56 to which the display scanning voltage is applied and the X-coordinate electrode 56 to which the display data voltage is applied becomes a display voltage of a predetermined magnitude. Then, a predetermined display electric field having such a strength as to change the state of the liquid crystal layer from the steady state is generated.

Therefore, for example, of the pixels in the one row including the Y coordinate electrode 56 to which the display scanning voltage is applied, the pixel to which the display voltage is applied to the X coordinate electrode 56 is a black pixel that blocks light, and The liquid crystal layer of each pixel becomes a white pixel that transmits light. By sequentially performing such an operation for each row in the direction in which the Y coordinate increases, the display state of all pixels in the display detection area is determined, and an image is visually displayed by a combination of these pixels. You. When the liquid crystal display device performs color display, a single pixel is formed by arranging in the X direction three monochromatic pixels covered with a filter that transmits red, blue, and green monochromatic lights. The display state is determined as described above.

The state of the liquid crystal layer is determined by the X and Y coordinate electrodes 56,
It is determined by the value of the voltage between 57. When this voltage value is changed, the time required for the state change of the liquid crystal layer in conjunction with the voltage change is longer than the time required for the voltage change.
Immediately after the voltage change, the state of the liquid crystal layer is maintained. The single coordinate detection operation is a period following the above-described display period,
This is performed within a coordinate detection period in which the state of the liquid crystal layer determined in the display period can be maintained. As a result, during the coordinate detection period, an image visually displayed in the display detection area of the liquid crystal display device 28 during the display period is held.

The operator of the electronic device 21 is
8 while visually observing the image visually displayed in the display detection area.
The pen member 3 is placed at a desired position in the same display detection area.
4 is brought into contact. As a result, at the pixel located immediately below the designated point where the tip of the pen member contacts, the X coordinate electrode 5
6 is a pen member 34 via one substrate of the liquid crystal display device 28.
And the Y coordinate electrode 57 approaches the indicator electrode of the pen member 34 via the one substrate of the liquid crystal display device 28 and the liquid crystal layer. When a predetermined detection voltage is applied to each of the X and Y coordinate electrodes 56 and 57 passing through the pixel immediately below the designated point and charged, the designated electrode and the coordinate electrodes 56 and 57 are electrostatically coupled, and the designated electrode and the coordinate electrodes 56 and 57 are electrostatically coupled. , An induced voltage is induced. The electrostatic coupling type tablet device applies a detection voltage to each of the plurality of X and Y coordinate electrodes 56 and 57 of the liquid crystal display device 28 sequentially and individually, and charges the X and Y coordinate electrodes while inducing the induced voltage induced on the indicator electrode. The position coordinates of the pixel where the X and Y coordinate electrodes 56 and 57 intersect when the induced voltage is detected are obtained as the position coordinates of the designated point.

The switching between the display operation and the coordinate detection operation is performed by a switching circuit 42, which switches a signal to be given to the liquid crystal display device 28 from a display control signal for the display operation to a detection control signal for the coordinate detection operation. This is done by: The switching cycle of these control signals is determined by the central processing circuit 37.
Is controlled by a switching control signal generated by the switching control unit 50 of the first embodiment. This switching cycle is changed in conjunction with, for example, a change in the signal transmission / reception speed of the host device 23 and the display control circuit 31 and a change in the data bit length of the liquid crystal display device. At this time, since the switching control unit 50 generates the switching control signal by the arithmetic processing, the switching cycle can be changed only by changing the arithmetic processing. Therefore, since there is no need to change the circuit structure, it can be easily changed.

Hereinafter, the coordinate detecting operation in the electronic device 1 will be described in detail.

FIG. 11 is a block diagram schematically showing a main processing operation performed by central processing circuit 37. Electronic device 2
1 is supplied with power, the steps a1 to a
Proceed to 2.

At step a2, the display detecting device 24 is initialized. Specifically, first, it is determined whether or not the central processing circuit 37 has a failure. Also, a timer 38, a memory 40
In the work area and the register group 43, predetermined initial values are set. When the initialization is completed, the display detection device 24 is in a state where the coordinate detection operation and the command processing operation can be performed.

Subsequently, at step a3, the central processing circuit 3
7 refers to the value of the coordinate detection flag represented by bit b0 of the flag register 95 to determine whether or not to execute the coordinate detection operation. The coordinate detection flag indicates that the coordinate detection operation is performed when the value is 1, and indicates that the coordinate detection operation is not performed when the value is 0. Flag register 9
When the value of the bit b0 of 5 is 1, the process proceeds from step a3 to step a4 to execute the coordinate detection operation, and after the coordinate detection operation ends, the process proceeds from step a4 to step a5. Details of the coordinate detection operation will be described later. For example, since the initial value of bit b0 of flag register 95 is set to 0, immediately after the end of the initialization operation in step a2,
The process proceeds directly from step a3 to step a5.

At step a5, the central processing circuit 37
Referring to the contents stored in command register 93, it is determined whether or not a command signal has been written. When the command signal is being written, the process proceeds from step a5 to step a6, and the command processing operation represented by the written command signal is performed. Details of the command processing operation will be described later. Upon completion of the command processing operation, the flow returns from step a6 to step a3. If it is determined in step a5 that the command signal has not been written to the command register 93, the process proceeds from step a5 to step a2.
Return to Thereafter, the processing operations of steps a3 to a6 are repeated until the supply of power in the electronic device 21 is stopped.

During the repetition of steps a3 to a6, for example, in response to an instruction from central processing circuit 26 of host device 23, central processing circuit 37 generates a command signal for instructing a coordinate detecting operation, and generates a command signal in command register 93. In the command processing operation of step a6, the value of the bit b0 of the flag register 95 is updated to 1 as described later. Thus, when the process returns from step a6 to step a3 again, the value of the coordinate detection flag indicates that the coordinate detection operation is to be performed in step a3. Therefore, the process proceeds from step a3 to step a4, and the coordinate detection operation is performed. Do. When a command signal is written in the command register 93 during the coordinate detecting operation in step a4, steps a5 and a5 performed after step a4 are executed.
At 6, the command processing operation is performed. As a result, the coordinate detection operation and the command processing operation can be performed by the same central processing circuit 37.

FIG. 12 is a flowchart for schematically explaining the coordinate detection operation of the central processing circuit 37 performed in step a4 of the processing operation of FIG. FIG.
In the first main processing operation, the process proceeds from step a3 to step a4. When the coordinate detection operation is started, the process proceeds from step c1 to step c2. In step c2, the central processing circuit 3
7 initializes the interface circuit 41. More specifically, first, the control register 92 is initialized by setting the values of the bits b0 to b7 of the control register 92 to initial values. Further, a switching control signal is generated and the switching circuit 42 is switched so that the control signal given from the interface circuit 41 to the liquid crystal display device 28 becomes the detection control signal from the central processing circuit 37. Further, the data register 9
1 and the contents stored in the control register 92 are rewritten by each individual signal of the detection control signal. As a result, the interface circuit 41 is set to a state in which various signals used in the coordinate detection operation are exchanged. When the initialization of the interface circuit 41 is completed, the process proceeds to step c3.

In Step c3, the Y of the liquid crystal display device 28
The directional scanning operation is performed, and the Y coordinate of the designated point designated by the pen member 34 is detected. Details of the Y-direction scanning operation will be described later. When the Y-direction scanning operation is completed, the process proceeds from Step c3 to Step c4, and it is determined whether or not the Y coordinate is not detected in the Y-direction scanning operation. When the Y coordinate is detected, the process proceeds from step c4 to step c5, where the liquid crystal display device 28 performs an X-direction scanning operation to detect the X coordinate of the designated point. The details of the X-direction scanning operation will be described later. When the X-direction scanning operation is completed, the process proceeds from Step c5 to Step c6, and it is determined whether or not the X coordinate is not detected in the X-direction scanning operation. When it is determined that the X coordinate has been detected,
The process proceeds from step c6 to step c7.

In step c7, the X and Y coordinates detected in the X and Y direction scanning operations in steps c3 and c5 are corrected. Subsequently, in step c8, the bit b5 of the status register 94 is reset, and the bit b6 is set and updated. “Resetting a bit of a register” means that the value of the bit is set to “0”. “Setting a bit of a register” means that the value of the bit is set to “1”. Bit b5 of the status register 94 indicates that the designated point is present when reset, and indicates that the designated point does not exist when set.
Bit b6 of the status register 94 indicates that the coordinate detection operation has been performed when set, and indicates that it has not been performed when reset. When the update of the status register 94 is completed, the process proceeds from step c8 to step c9, and the processing operation of the flowchart ends.

When it is determined in step c4 that the Y coordinate is not detected, and when it is determined in step c6 that the X coordinate is not detected, the central processing circuit 37 determines that the operator of the device 21 has the pen member 34 Judge that it is not used. That is, it is determined that the designated point has not been designated in the display detection area of the liquid crystal display device 28. In this case, the process proceeds from Steps c4 and c6 to Step c8.
At this time, the central processing circuit 37 outputs the status register 94
The bit b5 and bit b6 are set and updated, respectively, and the processing operation of the flowchart ends in step c9.

The central processing circuit 37 constantly monitors the status register 94 during execution of the main control processing of FIG. 11, and waits until the bit b6 is set in step c8 of FIG. Upon confirming that the bit b6 of the status register 94 has been set, the central processing circuit 37 generates a command signal instructing a coordinate reading operation, and stores the command signal in the command register 93. Therefore, when the coordinate processing operation is performed in step a4 of the flowchart of FIG. 11 described above, the coordinate reading operation is performed in the command processing operation of step a6 immediately after that. As a result, the central processing circuit 37 can acquire the coordinates of the designated point.

FIG. 13 shows the central processing circuit 37 executed in step c3 of the flowchart of the coordinate detecting operation of FIG.
5 is a flowchart for explaining in detail the Y-direction scanning operation.

In the flowchart of FIG. 12, the process proceeds from step c2 to step c3. When the Y-direction scanning operation is performed, the process proceeds from step d1 to step d2. Step d
In 2, the central processing circuit 37 transfers the total number of the Y coordinate electrodes 57 stored in the Y direction scanning line number register to the scanning line number register and stores it in a Y direction scanning line number register setting operation described later. Next, bits b1 and b2 of the model register 96 set by a panel member setting operation described later.
, It is determined whether the structure of the liquid crystal display device 28 is a single panel structure or a dual panel structure. In the case of the dual panel structure, the process proceeds from step d3 to step d4. Set again. This is because in the Y-direction scanning operation of the liquid crystal display device 61 having the dual panel structure, the first and second panel members 62,
This is for simultaneously scanning each of 63. When the resetting of the number of scanning lines in the Y direction is completed, the process proceeds to step d5.
When the structure of the liquid crystal display device 28 is a single panel structure, the process directly proceeds from step d3 to step d5.

At step d5, all bits b0 to b15 of the data register 91 are reset to "0". Then
In step b6, the signal generator 48 sets the control register 92
The data signal currently stored in the data register 91 is repeatedly supplied from the interface circuit 41 to the X coordinate electrode control circuits 53; 64, 65 for each pulse cycle of the clock signal with reference to the bit b0 of FIG. For example, when the liquid crystal display device 28 is a device for displaying a black-and-white image, the number of transmissions of the data signal is determined by the value stored in the X-direction scanning line number register in the X-direction scanning line number setting operation described later. This is the number of times the data bit length of the device 28 is divided by the data width. In addition, when the liquid crystal display device 28 is a device that displays a color image, the number of times is three times the number of times in black and white. At this time, all bits b of the data register 91
Since 0 to b15 are reset, the X coordinate electrode control circuits 53; 64, 65 do not apply the detection voltage to all the X coordinate electrodes 56. As a result, all the X-coordinate electrodes 56 are not charged, so that no induced voltage is induced on the indicator electrodes even if the indicator electrodes of the pen member 34 approach.

Subsequently, in step d7, a scanning method for obtaining a coordinate position is determined with reference to bit b2 of the flag register 95. In the display detection device 24, there are two methods, a pulse scanning method for obtaining coordinates using a latch pulse signal described later, and a time scanning method for obtaining coordinates using the elapsed time from the start of the scanning operation to the detection of the coordinates. Can be selected by the operator of the device 21. The scanning method selected by the operator is stored in advance in bit b2 of the flag register 95. For example, when set, it indicates that the time scanning method is selected, and when reset, the pulse scanning method is selected. It represents that. If it is determined in step d7 that the time scanning method has been selected, the process proceeds from step d7 to step d8. When it is determined that the pulse scanning method is selected, the process proceeds from step d7 to step d17.

Steps d8 to d15 are a Y coordinate detection operation using the time scanning method. At step d8, the central processing circuit 37 initializes the timer 38. Specifically, first, the elapsed time measured by the timer 38 is set to 0.
Then, the value of the set value used in the operation of the timer 38 is returned to the initial value and updated. Further, the latch circuit of the timer 38 is released. The signal generator 48 sends a frame signal from the interface circuit 41 to the liquid crystal display device 28 with reference to the bit b2 of the control register 92, and the Y coordinate electrode 57 arranged at the position where the Y coordinate is 0. To
The Y coordinate electrode control circuit 54; 66, 67 selects the specific coordinate electrode to which the detection voltage is to be applied. At this time,
In the liquid crystal display device 51 having the single panel structure, any one of the all coordinate electrodes 57 of the panel member 52 is set as the specific coordinate electrode. In the liquid crystal display device 61 having the dual panel structure, the first and second panel members 6
Since specific coordinate electrodes are set in each of 2 and 63, two specific coordinate electrodes are set in the entire device 61.

Next, in step d9, the timer 38 is caused to start the operation of elapse of the elapsed time. Then, step d1
0, the signal generator 48 sets the bit b of the control register 92
1, a latch pulse signal whose pulse rises in synchronization with the pulse of the clock signal is created, and this latch pulse signal is sent from the interface circuit 41 to the liquid crystal display device 28. Thereby, the Y coordinate electrode control circuit 5
4: 66, 67 selects the new Y coordinate electrode 57 as a specific coordinate electrode and scans all the Y coordinate electrodes 57 so as to apply a detection voltage only to the specific coordinate electrode.

Next, at step d11, the timer 38
It is determined whether or not the latch circuit stores the elapsed time, thereby determining whether or not the instruction signal from the determination circuit 18 has been detected. That is, it is determined whether the Y coordinate electrode, which is the specific coordinate electrode, and the pointing electrode of the pen member 34 have been electrostatically coupled. When it is determined that the instruction signal has not been detected, the process proceeds to step d12.

In step d12, it is determined whether or not the determination operation in step d11 for the current specific coordinate electrode has been repeated a predetermined number of times n. “N” represents an arbitrary integer. If the number of repetitions is still less than n, the process returns to step d11, and the determination operation is performed again. This is performed in order to improve the accuracy of the coordinate determination in the Y coordinate detection operation of the time scanning method. The number of repetitions can be changed by setting a value of an n counter described later. When it is determined in step d12 that the determination operation in step d11 has been repeated n times, the instruction signal has not been detected in all the n determination operations in step d11, and the process proceeds from step d12 to step d13.

In step d13, first, 1 is subtracted from the value currently stored in the scan line number register to update the value. Next, it is determined whether or not the updated value of the scan line number register is 0. If it is not 0, it is considered that there is still a Y coordinate electrode 57 that is not a specific coordinate electrode. Therefore, the process returns from step d13 to step d10, and the operations of steps d10 to d13 are repeated using the next Y coordinate electrode 57 as the specific coordinate electrode. This step d10
The operations from to d13 are repeated until the updated value of the scan line number register becomes 1, or until an instruction signal is detected in step d11. When the updated value is 0, it is considered that the determination operation of step d11 is performed for all the Y coordinate electrodes 57, and that no instruction signal is detected in all the determination operations. At this time, there is no point indicated by the pen member 34 in the display detection area of the liquid crystal display device 28. Therefore, when the updated value is 0, the process proceeds from step d13 to step d14.

At step d14, the flag register 95
By updating the bit b3 of the pen member 3
4 indicates that the designation of the designated point using No. 4 has not been performed. After updating the flag register 95, step d
The process proceeds from step 14 to step d25, and the processing operation of the flowchart is ended.

In step d11, the timer 3
8 is set and it is determined that the instruction signal has been detected, the steps d11 to d11 are performed.
Proceed to 15. In step d15, the coordinate detecting unit 49
The elapsed time stored in the latch circuit of the timer 38 is obtained, and the Y coordinate is obtained from the elapsed time using the following equation.

Y coordinate = elapsed time / unit time (1) A specific value of the Y coordinate is a quotient of the above equation. The unit time is
It is set to be equal to or less than the processing time required for the processing operation of steps d10 to d13 for a single specific coordinate electrode, that is, a time period for applying a detection voltage to a single Y coordinate electrode 57,
Can be changed. When the unit time coincides with the processing time, the right side of the above equation is changed from the coordinate electrode 57 arranged at the position where the Y coordinate is 0 to the specific coordinate electrode 5 electrostatically coupled to the indicator electrode.
7 represents the number of Y coordinate electrodes 57 up to 7. Thus, the value of the Y coordinate is obtained by the processing operations of steps d8 to d15. When the processing operation in step d15 ends, the flow advances to step d16.

In step d16, the signal generator 48
The pulse of the latch pulse signal is continuously derived from the interface circuit 41. As a result, the Y coordinate electrode control circuits 54; 66, 67 are controlled such that the specific coordinate electrode becomes the Y coordinate electrode 57 outside the display detection area. This is performed to remove all the Y coordinate electrodes 57 from the specific coordinate electrodes in order to perform the X coordinate scanning operation following the Y coordinate scanning operation. When the specific coordinate electrode is moved out of the display detection area, the process proceeds from step d16 to step d25, and the processing operation of the flowchart ends.

If it is determined in step d7 that the pulse scanning method is selected, the process proceeds from step d7 to step d17. Steps d17, d20 to d24 are:
This is a Y coordinate detection operation using a pulse scanning method. Since the pulse scanning method and the time scanning method are similar, detailed description of the steps for performing the same operation will be omitted.

At step d17, 0 is substituted into the LP counter for initialization. The LP counter is set in the interface circuit 41, for example. In addition, the signal generation unit 489 transmits the signal from the interface circuit 41 to the liquid crystal display device 2.
8, the frame signal is transmitted with reference to bit b2 of the control register 92. Step d17 to step d2
Go to 0.

At step d20, a latch pulse signal is generated to control the Y-coordinate electrode control circuit 54; When the instruction signal is detected, it is determined whether or not the determination operation in step 21 has been performed on all the Y coordinate electrodes 57 in step d22. Each processing operation in steps d20 to d22 is equal to the processing operation in steps d11 to d13. When it is determined in step 22 that the updated value of the scan line number counter is not 0, the process proceeds to step d23, in which the value of the LP counter is updated by adding 1, and the process returns to step d20. The processing operations in steps d20 to d23 are repeated until an instruction signal is detected in step d21, or until the updated value becomes 0 in step d22.

When the instruction signal is detected in step d21, the process proceeds to step d24, and the value of the LP counter is obtained as it is as the value of the Y coordinate. Next, step d24
The process proceeds from step d16 to step d16 to move the specific coordinate electrode out of the display detection area, and then ends the processing operation of the flowchart in step d25. Also, in step d22,
When the updated value of the scanning line number register is 0, the process proceeds from step d22 to step d14, and after updating bit b3 of the flag register 95, step d2
At 5, the processing operation of the flowchart ends.

As described above, the display detection device 24 of the present embodiment is
Then, the Y coordinate can be obtained using two types of scanning methods. Among these scanning methods, the pulse scanning method has a simple processing operation, so that the time required for the processing operation can be reduced. Further, in the time scanning method, since the detection operation of the instruction signal is repeated a plurality of times, the detection accuracy of the instruction signal can be improved, and the detection omission of the Y coordinate can be prevented. Further, the processing operation of step d21 may be repeatedly performed by the pulse scanning method, and the repetition number n of step d12 may be set to 1 and the repetition operation may not be performed by the time detection method.

Further, since the value of the scanning line number register is determined in accordance with the structure of the liquid crystal display device 28, the pulse and time scanning methods are implemented for each of the two types of liquid crystal display devices 51 and 61. can do. At this time, in the liquid crystal display device 61 having the dual panel structure, since the Y coordinate electrodes 57 of the first and second panel members 62 and 63 are simultaneously scanned, the Y coordinate electrode 57 electrostatically coupled to the indicator electrode is moved to the second position. It is not possible to determine which of the first and second panel members is the Y coordinate electrode 57, and the Y coordinate has not been determined. The determination of the Y coordinate obtained by the liquid crystal display device 61 having the dual panel structure is performed in an X coordinate scanning operation described later.

FIGS. 14 and 15 show the central processing circuit 3 implemented in step c5 of the coordinate detecting operation of FIG.
7 is a flowchart for explaining the X-direction scanning operation of FIG. 7 in detail.

The X-direction scanning operation is an operation similar to the Y-direction scanning operation. The specific coordinate electrode is the X coordinate electrode 56 and the X coordinate electrode control circuit 53;
4, 65, and the operation when using the liquid crystal display device 61 having a dual panel structure is different, and the other operations are the same. Of the flowcharts in FIGS. 14 and 15,
A detailed description of steps for performing the same operation as in the flowchart of FIG. 13 will be omitted.

In the flowchart of FIG. 12, the process proceeds from step c4 to step c5. When the X-direction scanning operation is started, the process proceeds from step e1 to step e2. Step e
In step 2, the liquid crystal display device 2 operates in the same manner as in step d3.
8 are determined. When the structure is a single panel structure, the process proceeds from step e2 to step e3. When the structure is a dual panel structure, the process proceeds from step e2 to step e25.
Proceed to.

In step e3, the number of output times of the data signal is calculated. As described above, the X coordinate electrode control circuit 5
3: 64, 65 can transmit and receive a plurality of bits of the data signal in parallel. Therefore, dividing the data signal into a plurality of divided data signals and transmitting and receiving each of the divided data signals in parallel, rather than transmitting and receiving each bit of the data signal in series, shortens the time required for transmitting and receiving the data signal. The processing time of the directional scanning operation can be reduced. Details of this data signal will be described later. The number of data transmissions is represented by the following equation.

[0105]

(Equation 1)

In a color image liquid crystal display device, the number of X coordinate electrodes is three times that of a black and white image liquid crystal display device. Therefore, the resolution, that is, the resolution is three times higher than that of a black and white image liquid crystal display device. .

Next, at step e4, 0 is substituted into a data counter for counting the number of times of data output to initialize. Subsequently, in step e5, 0 is substituted into a detection counter for counting the number of times the X-coordinate detection operation described below is performed, and is initialized. The data counter and the detection counter are provided, for example, in the interface circuit 41.

Subsequently, in step e6, step d7
The selection result of the scanning method is determined in the same manner as described above. When the time scanning method is selected, steps e7 to e1
7 is performed. When the pulse scanning method is selected, the processing operations of steps e18 to e24 are performed.

In step e7, the timer 38 is initialized as in step d8.
8 is started. In step e9, the signal generator 48 converts the divided data signal and the latch pulse signal into the liquid crystal display device 28 via the interface circuit 41.
Give to. In the operation of deriving a data signal, first, the data signal corresponding to the current number of data outputs is read from the memory and divided, and the data register 91 stores the divided data signal. Next, the interface circuit 41 refers to the data register 91, and causes the interface circuit 41 to derive the divided data signal to the X coordinate electrode control circuits 53; When this operation is repeated for the number of divisions of the data signal,
X-coordinate electrode control circuit 53 for all bits of the data signal;
64, 65. A plurality of data signals are prepared, and the position of the X coordinate electrode to which the detection voltage is to be applied differs for each data signal.

The operation of deriving the latch pulse signal is performed in step d.
Equivalent to 10. At this time, a latch pulse signal is supplied to both the X and Y coordinate signal control circuits 53 and 54; 64-67. However, in step d16 of the Y direction control operation, the specific coordinate electrode of the Y coordinate electrode is moved out of the display detection area. Since it has been moved, the specific coordinate electrode does not return to the display detection area even if the latch pulse signal is further applied. Therefore, even if the indicator electrode approaches the Y coordinate electrode 57, no electrostatic coupling occurs. As a result, the X coordinate electrode control circuit 53;
A detection voltage is applied.

Next, in steps e10 to e12, X
The detection operation of the coordinate electrode 56 with respect to the specific coordinate electrode is performed. The processing operations of steps e10 and e11 are the same as the processing operations of steps d11 and d12, ie, step e12.
Is different from the value of the scan line number register only in that the number of data outputs stored in the data counter is used. Other processing operations are the same as those in step d13. this is,
This is because, in the X-direction scanning operation, the latch pulse signal is used as the latch signal for outputting the data signal, so that the number of outputs of the latch pulse signal does not directly relate to the X coordinate.
Further, when returning from step e12 to step e9 to derive the data signal again, the data signal is changed according to the number of data outputs, so a signal different from the previous data signal is used.

When the instruction signal is detected in step e10, the process proceeds from step e10 to step e14, where 1 is added to the value of the detection counter for updating. Further, it is determined whether or not the updated value of the detection counter is 2. When the updated value is not 2, that is, at the end of the first detection operation, the process proceeds from step e14 to step e15, and the elapsed time obtained in the first detection operation is added to the operation variable T1 by the timer 38. Provided from the latch circuit and stored. Further, after the timer 38 is re-initialized, the timer operation is started, and after the signal generation unit 48 returns the data signal and the latch pulse signal to the first signal, the process returns from step e15 to step e9. As a result, steps e9 to e1 are repeated using the same plurality of data signals.
2 is performed. When the updated value is 2, that is, at the end of the second detection operation, the process proceeds from step e14 to step e16, and the elapsed time obtained in the second detection operation is added to the operation variable T2 by the timer. The data is supplied from the latch circuit 38 and stored. As described above, the operation of detecting the X coordinate is repeatedly performed twice.
Omission of detection of the X coordinate can be further prevented.

At step e17, the X-coordinate value is obtained by the following equation using the values of the operation variables T1 and T2 in the coordinate detecting section 49.

X coordinate = (T1 + T2) / (2 × unit time) (3) The X coordinate is obtained from an average value of elapsed time obtained by two detection operations. Therefore, the accuracy of the X coordinate can be improved as compared with the case where the detection operation is performed only once.
When the X coordinate is obtained, the processing operation of the flowchart ends in step e49.

In the first or second detection operation in steps e9 to e12, if the instruction signal is not obtained and the updated value of the number of data outputs is 0, step e12
From step e13. In step e13, after the fact that there is no point indicated by the pen member 34 is stored in the flag register 95 by the same operation as step d14,
In step e49, the processing operation of the flowchart ends.

Further, when it is determined in step e6 that the pulse scanning method is selected, the process proceeds from step e6 to step e18. In step e18, the signal generator 48 provides the data signal and the latch pulse signal to the liquid crystal display device 28 by the same operation as in step e9. Next, in step e19, the same operation as in step d21 is performed.
It is determined whether an instruction signal has been detected. If not detected, in step e20, the value of the data output count is updated by the same operation as step e12, and it is determined whether or not the updated value is 0. When it is 0,
The process proceeds from step e20 to step e13, and after the fact that there is no designated point is stored in the flag register 95, the processing operation of the flowchart is ended in step e49.

When the instruction signal is detected in step e19, the flow advances to step e21 to determine whether the operation of detecting the instruction signal is the first operation or the second operation in the same operation as in step e14. At the first time, at step e22, the number of outputs of the latch pulse signal in the first detection operation is substituted for the operation variable T1 and stored, and then the signal and the timer are returned to the initial state as at step e15. Returning to step e18,
The second detection operation is performed. At the second time, at step e23, the number of outputs of the latch pulse signal in the second detection operation is substituted for the operation variable T2 and stored.
Proceed to 24. The number of times of output of the latch pulse signal can be obtained, for example, by calculating a difference value between the initial value of the number of times of data output calculated in step e3 and the value of the number of times of data output updated in step e20.

In step e24, the coordinate detecting section 49 sets
The X coordinate is obtained from the values of the operation variables T1 and T2. This X
For example, the average value of the values of the operation variables T1 and T2, that is, the average value of the number of times of output of the latch pulse signal, is substituted into the coordinates. When the X coordinate is obtained, step e4
In step 9, the processing operation of the flowchart ends.

Further, when it is determined in step e2 that the structure of the liquid crystal display device 28 is a dual panel structure, the process proceeds from step e2 to step e25. The liquid crystal display device 61 having a dual panel structure has two panel members 6.
X and Y coordinate electrodes 56,
57 exist. In the above-described Y-direction scanning operation, since the two panel members 62 and 63 are simultaneously scanned, the Y coordinate is not determined. In the X-direction scanning operation, the second panel member 6 is used to determine the Y coordinate while obtaining the X coordinate.
An X-direction scanning operation is individually performed on each of 2, 63.

First, in step e25, 1 is assigned to bit b5 of the flag register 95, so that the first
The first panel member 62 is selected as the panel member to be scanned among the second panel members 62 and 63. Next, the processing operations of steps e26 to e35 are performed. These processing operations are the same as the processing operations of steps e3 to e12. At this time, since only the first panel member 52 is scanned, in the output operation of the data signal in step e32, the signal generation section 48 outputs all the bits b0 to b of the data register 91.
15, bits b0 to b7 given to the first X coordinate electrode control circuit 64 store bits of the data signal,
Bits b8 to b8 applied to the second X coordinate electrode control circuit 64
b15 is forcibly set to 0.

When it is determined in step e33 of this processing operation that the pointing signal has been detected, it is determined that the pointing point specified by the pen member 34 is on the first panel member 62, and the Y coordinate is the Y coordinate scanning operation. Is determined by the value obtained in. In this case, the process proceeds from step e33 to step e36, and the number of times of the operation of detecting the instruction signal in steps e32 to e35 is determined by the same operation as step e14. In the case of the first time, in step e37, step e15
A value is substituted for the operation variable T1 by the same operation as that described above, the signal and the timer 38 are initialized, and the process returns to step e32 to perform the second detection operation. At the second time, step e38
Then, the value is substituted into the operation variable T2 by the same operation as in step e16, and the flow proceeds to step e17. In step e17, as described above, the coordinate detecting unit 49 sets the operation variables T1,
Using the value of T2, the X coordinate is calculated and obtained, and step e4
In step 9, the processing operation of the flowchart ends. As described above, when the X coordinate is obtained when the first panel member is set as the scanning target, the designated point is determined to be in the display detection area on the first panel member 62, and the Y coordinate is obtained by the Y coordinate scanning operation. Is determined.

When the updated value of the data output count is 0 in step e35, it is considered that the designated point is in the display detection area on the second panel member. In this case, the process proceeds from step e35 to step e39.
In step e39, the coordinate value corresponding to half the number of all the Y coordinate electrodes 57 is added to the Y coordinate obtained in the Y direction scanning operation and updated. Thereby, the Y coordinate is determined.

Next, at step e41, referring to bit b5 of the flag register 95, steps e26 to e
35, the first and second panel members 62, 6
3 is determined. When the first panel member 62 is to be scanned, the process proceeds to step e41, where 2 is substituted for the value of the bit b5 of the flag register 95 and updated. Thus, the second panel member 63 is selected as the panel member to be scanned. Thereafter, step e41
Then, the process returns to step e26, and the processing operations of steps e26 to e38 and e17 are performed on the second panel member 63. At this time, since only the second panel member 63 is scanned, in the output operation of the data signal in step e32, of the bits b0 to b15 of the data register 91, the bit given to the first X coordinate electrode control circuit 64 is selected. b
0 to b7 are forcibly set to 0, and data signals are stored in bits b8 to b15 provided to the second X coordinate electrode control circuit 64. In the processing operation of steps e26 to e38,
When the X coordinate on the second panel member 63 is obtained by calculation, the processing operation of the flowchart is ended in step e49. As described above, when the X coordinate is obtained when the second panel member 63 is to be scanned, the designated point is determined to be in the display detection area on the second panel member 63, and the Y coordinate is determined by the Y coordinate scanning operation. The first panel member 62
Is determined to a value obtained by adding the value of the Y coordinate of the display detection area of.

In steps e33 to e35, no instruction signal is obtained even in the detection operation of all X coordinate electrodes, and step e4 is performed.
When it is determined at 0 that the second panel member 63 is to be scanned, it is determined that the X coordinate cannot be obtained. This X
Since the coordinate scanning operation is performed when it is determined that the designated point exists in the Y coordinate scanning operation, it is considered that the X coordinate can always be obtained. However, for example, there is an error in the Y coordinate scanning operation. At times, the X coordinate may not be obtained. At this time, in step e42, step e1
After the fact that there is no designated point in the same operation as in step 3 is stored in the flag register 95, the processing operation of the flowchart is ended in step e49.

Further, when it is determined in step e29 that the pulse scanning method is selected, the process proceeds from step e29 to step e43, and in steps e43 to e45,
An operation of detecting an instruction signal is performed by the same operation as in steps e18 to e20. When a detection signal is detected, step e
In step 46, the same operation as in step e36 is performed, and step e4 is performed.
The number of times of the detection operation of 3 to e45 is determined. At the first time, in step e47, a value is substituted for the operation variable T1 by the same operation as step e22, the data signal is initialized, and the process returns to step e43 to perform the second detection operation. At the second time, the process proceeds to step e48, and in the same manner as in step e23, the number of times of output of the latch pulse signal is substituted for the operation variable T2. The processing operation of the flowchart ends. At this time, the Y coordinate is determined to a value obtained by the Y coordinate scanning operation.

When the updated value of the number of times of data output is 0 in step e45, the process proceeds from step e45 to step e39, where Y obtained in the Y-direction scanning operation is obtained.
The Y coordinate is determined by adding the coordinate value corresponding to half the number of all the Y coordinate electrodes to the coordinate and updating the coordinate. Then
The operation of determining the panel member to be scanned in step e40 is performed. When the first panel member 62 is scanned according to the result, the process returns to step e26 via step e41, and the second panel member 63 is processed. Again, steps e26 to e29, e43 to e45, e39, e4
0, e46 to e48 are performed. When the second panel member 63 is a scanning target, the fact that there is no designated point is stored in the flag register 9 by the same operation as in step e13 in step e42, and the processing operation of the flowchart is ended in step e49. I do.

Through such processing operations, the X coordinate is obtained and the Y coordinate is determined.

FIGS. 16 and 17 are schematic diagrams showing data signals output in the above-described X-direction scanning operation.
6 shows a case where the data bit length of the liquid crystal display device 28 is 4 bits, and FIG. 17 shows a case where the data bit length is 8 bits. The horizontal axis indicates the number of the X coordinate electrode 56, and the vertical axis indicates the number of data transmissions. In FIG. 2 and FIG. 3, the numbers of the X coordinate electrodes 56 are sequentially assigned to the X coordinate electrodes so that the numbers increase from the left end to the right end of the panel member. Each rectangular area indicates the presence or absence of application of the detection voltage to each X coordinate electrode 56 by color, a white rectangular area indicates that no detection voltage is applied, and a black rectangular area with hatching applies the detection voltage. To do so. FIG.
17, the number of X coordinate electrodes 56 is 30
Suppose it is a book.

At this time, when a detection voltage is applied to the X-coordinate electrode 56, a plurality of X-coordinate electrodes 56 having consecutive numbers are handled as one set. The pattern of voltage application to one set of X coordinate electrodes 56 is 2 in the number of one set of X coordinate electrodes 56.
There are patterns of the number obtained by adding. Hereinafter, the number is set to M. Of these patterns, for example, the first pattern applies a detection voltage to one set of all X coordinate electrodes 56. In the second pattern, no detection voltage is applied to one set of all X coordinate electrodes 56. In the third to M-th patterns, the detection electrode is applied to only one of the set of all X coordinate electrodes 56, and the detection voltage is not applied to the remaining X coordinate electrodes 56. Furthermore, in the third to M-th patterns, X to which the detection voltage is applied
The coordinate electrodes are all different. In FIG. 16, four X coordinate electrodes 5
6 as one set, there are first to sixth patterns, and specifically, correspond to the arrangement of the white / black areas of the areas 101 to 106. In FIG. 17, there are ten patterns with eight X coordinate electrodes 56 as one set.

When using this pattern to detect the X coordinate electrode 56 electrostatically coupled to the pointing electrode, two sets of X coordinate electrodes 56 are processed. First, one set of X coordinate electrodes 5
6, the detection voltage is applied in the first pattern, and the other set of X coordinate electrodes 56 is used as the second pattern. Thus, it is possible to determine whether or not the designated point designated by the pen member 34 exists on one set of the X coordinate electrodes 56. Next, one set of X coordinate electrodes 56 is used as the second pattern,
A detection voltage is applied to the coordinate electrode 56 in a first pattern. Thus, when the designated point cannot be detected in one set of X coordinate electrodes 56 in the first pattern, the other set of X coordinate electrodes 56
It can be determined whether there is an indication point above. As described above, it is possible to determine which of the first and second sets of X coordinate electrodes 56 has the designated point in the first and second patterns. Further, by sequentially applying the detection voltages in the third to M-th patterns to the set of X coordinate electrodes 56 for which the designated point has been detected by the above-described operation, the X coordinate electrodes 56 of the set are It is possible to determine on which X coordinate electrode 56 the designated point exists.

In order to carry out such a judging operation, in steps e9 to e12 in the flow charts of FIGS. 14 and 15, the X coordinate electrode control circuits 53; 64 and 65 are selected in a pattern as shown in FIGS. The detection voltage is applied. In this pattern, when only each group is individually viewed, the first to M-th patterns sequentially appear along the direction in which the number of data transmissions increases. Also, looking at a pattern that appears when the data is transmitted a certain number of times, the pattern number is delayed by one in the groups adjacent in the direction in which the number of the X coordinate electrode 56 increases.

For example, in a liquid crystal display device having a data bit length of 4 bits, for example, when the number of data transmissions is 6, the sixth to first patterns are the X coordinate electrodes 5.
The number 6 appears sequentially in the increasing direction, and the number 4
The detection voltage is applied to the X coordinate electrodes 56 of 7, 10, 13, 21 to 24, and the detection voltage is not applied to the remaining X coordinate electrodes 56. In a liquid crystal display device having a data bit length of 8 bits, for example, when the number of data transmissions is 4, the fourth to first patterns appear sequentially in the direction in which the number of the X coordinate electrode 56 increases. , Numbers 2, 9, 2
A detection voltage is applied to 5 to 30 X coordinate electrodes 56, and no detection voltage is applied to the remaining X coordinate electrodes 56.

The signal generator 48 of the central processing circuit 37 generates a data signal so that the detection voltage can be sequentially applied in such a pattern. The first to sixth patterns when the data width is 4 bits are “FF
FH "," 000H "," 0101H "," 0202 "
H, 0404H, and 0808H. The data signal is generated by combining these numerical values.
The central processing circuit 37 divides the data signal into 16-bit data to generate a divided data signal.
1 and further, the interface circuit 41 reads and outputs only the value of the bit corresponding to the data bit length.

FIG. 18 is a flow chart for explaining the data signal writing operation of the signal generation unit 48 of the central processing circuit 37 performed in steps e9, e18, e32 and e43 of the flow charts of FIGS. The data counter is provided, for example, in the interface circuit 41 and is used to determine from the interface circuit 41 what data application pattern indicates a data signal.

The above steps e9, e18, e32, e
When the processing operation of 43 is started, the process proceeds from step f1 to step f2. In step f2, it is determined whether or not the value of the data counter is 0. If so,
Proceeding from step f2 to step f3, "FFFFH" is selected as the data signal, and the selected data signal is divided and sequentially written to the data register 91. Otherwise, the process proceeds from step f2 to step f4.

By the same operation, steps f4 and f
At 6, f8, f10, f12, f14, f16, and f18, it is determined whether the value of the data register 91 is 1 to 8. If so, steps f5, f
The process proceeds to 7, f9, f11, f13, f15, f17, f19, and as data signals “0000H”, “0101”.
H "," 0202H "," 0404H "," 0808 "
H "," 1010H "," 2020H "," 4040 "
H ”is selected, and the selected data signal is divided and written into the data register 91. Otherwise, steps f4, f6, f8, f10, f12, f14, f1
From steps f6 and f18, steps f6, f8, f10, f1
2, f14, f16, f18, f20.
When the value of the data counter is not any of 0 to 8,
Proceeding from step f18 to step f20, "8080H" is selected as the data signal, and the selected data signal is divided and written into the data register 91. by this,
One of the data signals is selected.

Next, at step f21, 0 is substituted for the value of the data counter to initialize it. Further, step f
At 22, it is determined whether the data bit length is 4 bits and the value of the data counter is 5, and if so, after initializing the data counter at step f23, the flow chart at step f24 is executed. Is completed. Otherwise, the processing operation of the flowchart is terminated from step f22 to step f24. Thus, a 64-bit data signal is selected and sequentially written to the data register 91.

As described above, in the display detecting device 24, when the data bit length is 8 bits, the corresponding data signal is written into the data register 91, and the bits are limited when reading data from the data register 91. by this,
Using a single type of data signal, the X-direction scanning operation can be performed with a voltage application pattern suitable for the liquid crystal display device 28 having a different data bit length and a different panel member structure.

The Y coordinate electrode control circuit 54; 66, 6
7 is a circuit configured to be controlled by a data signal in the same manner as the X coordinate electrode control circuits 53; 64 and 65, the detection voltage application pattern to the Y coordinate electrode 57 is A pattern similar to the application pattern may be used. In this case, the X and Y coordinate electrodes 5
Each of the application patterns to 6, 57 may be a pattern in which the detection voltage is applied one by one, or the above-mentioned application pattern in which the detection voltage is applied to a plurality of pieces. Further, the application pattern to one of the X and Y coordinate electrodes 56 and 57 is a pattern for applying the detection voltage one by one, and the application pattern to one of the other coordinate electrodes is detected by plural pieces. A pattern for applying a voltage may be used.

FIGS. 19 and 20 are flow charts for explaining the command processing operation of the central processing circuit 37 performed in step a6 of the flow chart of the main control operation of FIG.

The command signal is supplied from the host device 23 and the display control circuit 31 to the interface 41.
At this time, the central control circuit 37 outputs the status register 94
Referring to the stored contents of the command register 93, when the write operation to the command register 93 is permitted,
Write a command signal to the address 3.

The flow advances from step a5 to step a6 in the flowchart of FIG. 11, and when the command processing operation is started, the flow advances from step g1 to step g2. Step g
In step 2, it is determined whether the contents stored in the command register 93 are a command code or command data. Command data should be read during the processing operation of a command signal requiring the data, and the command code should be read before execution of the command processing. If it is command data, the bit b0 of the status register 94 is rewritten and updated, and the central processing circuit 37 is notified that the command data has been written. If it is a command code, the process proceeds to step g4. Step g4 to g1
5 shows the structure and specifications of the liquid crystal display device 28 to be used,
This is a processing step for setting the display detection device 24. The command data of the command signal for instructing these setting operations represents data to be set, as described later.

At step g4, it is determined whether or not the command code indicates the setting operation of the number of scanning lines in the X direction. If so, go to step g5; otherwise, go to step g6. In step g5, as the setting operation, command data indicating the total number of the X coordinate electrodes 56 of the liquid crystal display device 28 is read from the command register 93, transferred to the X direction scanning line number register, and stored. At step g6, it is determined whether or not the command code indicates an operation for setting the number of scanning lines in the Y direction. If so, proceed to step g7; otherwise, proceed to step g8. In step g7, as the setting operation, command data indicating the total number of Y coordinate electrodes 57 of the liquid crystal display device 28 is read from the command register 93, and X
The data is transferred to and stored in the direction scan line number register.

In step g8, it is determined whether or not the command code indicates an operation for setting the structure of the panel member of the liquid crystal display device. If so, go to step g9, otherwise go to step g10. In step g9, as the setting operation, command data representing the structure of the liquid crystal display device 28 is read from the command register 93, the structure of the device 28 is specified from the command data, and bits b0 to b2, b7 of the model register 96 are set. Among them, 1 is set to a bit representing the specified structure, and the remaining bits are reset to 0. Further, the data bit length of the data signal of the liquid crystal display device 28 is specified from the command data, and the bits b3 and b4 of the model register 96 are set so as to represent the specified data bit length.

At step g10, it is determined whether or not the command code indicates the setting operation of the scanning method in the X and Y direction scanning operations of the coordinate detecting operation. If so, go to step g11; otherwise, go to step g1.
Proceed to 2. In step g11, as the setting operation, command data instructing the scanning method is stored in the command register 9.
3, the scanning method selected by the operator of the apparatus 21 is specified from the command data. When the time scanning method is used, the bit b2 of the flag register 95 is set to 1;
When the panel scanning method is used, the bit b2 is reset to 0.

At step g12, it is determined whether or not the command code indicates the start and stop of the coordinate detecting operation. If so, proceed to step g13; otherwise, proceed to step g16. Step g13
First, it is determined whether or not the command code indicates the start operation, and if so, the register group 43
It is determined whether or not various data required for the coordinate detection operation are stored in each of the registers. The various data are stored in the register group 43, and when it is determined that the stored content is appropriate and the coordinate detection operation can be performed, the process proceeds from step g13 to step g14, where the bit b0 of the flag register 95 is reset. Update. Thus, after the processing operation of the flowchart is completed, the coordinate detection operation can be performed. When there is a register in the register group 43 in which the various data has not been stored yet, the process proceeds from step g3 to step g15. At Step g15, the bit b1 of the status register 94 is updated, and at Step g30, the processing operation of the flowchart is ended. Thus, when the central processing circuit 37 refers to the status register 94, it is possible to know that the coordinate detection operation cannot be performed.

In step g16, it is determined whether or not the command code indicates whether or not to interrupt the coordinate detection operation. If so, go to step g17; otherwise, go to step g18. In step g17, the bit b7 of the flag register 95 is set to 1 when interrupt processing is permitted, and the bit b7 is reset to 0 and updated when interrupt processing is prohibited, in accordance with the instruction of the command code. Thereby, the coordinate detection operation can be performed in a pseudo-parallel with other processing operations by so-called interrupt processing.

At step g18, it is determined whether or not the command code instructs the lighting device 29 to be turned on or off. If so, go to step g19; otherwise, go to step g20. In step g19, the bit b6 of the flag register 95 is set to 1 when the light is turned on, and the bit b6 is reset to 0 and updated when the light is turned off in accordance with the instruction of the command code. As a result, the central processing circuit 37 communicates with the host device 2
In accordance with the instruction from the third device, the turning on and off of the lighting device 29 can be controlled. Also. When the luminance of the lighting device 29 can be changed in a plurality of discrete steps or continuously, the value of the flag register may be set according to the luminance.

At step g20, it is determined whether or not the command code instructs the operation of reading the detected X and Y coordinates. If so, go to step g21; otherwise, go to step g24. In step g21, it is determined with reference to bit b6 of the status register 94 whether or not the coordinate detection operation has been completed. When it is determined that the process has been completed, the process proceeds from step g21 to step g22. In step g22, first,
The form of the data representing the X and Y coordinates stored in the memory 40 is changed to a form that can be exchanged between the host device 23 and the display detection device 24, and is transferred from the interface circuit 42 to the host device 23. . At the same time, the bit b4 of the status register 94 is updated to return the display detection device 24 to the initial state. When it is determined that the coordinate detection operation has not been completed, the process proceeds from step g21 to step g23. At step g23, the bit of the status flag 94 is updated, and at step g30, the processing operation of the flowchart is terminated. Thereby, when the central processing circuit 37 refers to the status register 94,
It can be known that the coordinate reading operation cannot be performed.

In step g24, it is determined whether or not the command code instructs the setting operation of the numerical value n of the number of repetitions when the operation of detecting the instruction signal is repeated in the X and Y scanning operations of the coordinate detecting operation. If so, step g
Proceed to step g25, otherwise proceed to step g26.
In step g25, as the setting operation, command data representing the numerical value n of the number of repetitions is read from the command register 93, and transferred to the n register for storage.

At step g26, it is determined whether or not the command code indicates a reset operation for initializing the display detecting device 24. If so, step g
Proceed to step 27, otherwise proceed to step g29.
In step g27, an instruction is given to execute the processing in step a2 of the flowchart of the main control operation, and in step g30, the processing operation in the flowchart is terminated. When this instruction is issued, after the command processing in step a6 of the flowchart of the main control operation is completed, the central processing circuit 37
Returns to step a2 instead of step a3.

Steps g3, g5, g7, g9, g1
When the various processing operations are completed in steps 1, g14, g17, g19, g22, and g25, respectively, the process proceeds from each of the above-described steps to step g28. At step g28, bit b4 of the status register 94 is set and updated. After updating, the processing operation of the flowchart is ended in step b28. Thus, the central processing circuit 37 can know that the command processing has been completed normally by referring to the contents stored in the status register 94.

When the command code is set at step g2,
g4, g6, g8, g10, g12, g16, g18,
When it is determined that none of the various operations determined by g20, g24, and g26 is instructed, the command signal stored in the command register 93 is output to the display detection device 24.
Does not match any of the various command signals set in the command signal, it is considered that the command signal itself has an error. At this time, from step g26 to step g29
Proceed to. In step g29, the status register 94
Is set and updated. After updating, the processing operation of the flowchart is ended in step b28. Thus, the central processing circuit 37 can know that an abnormality has occurred in the command processing by referring to the storage contents of the status register 94.

As described above, the display detecting device 24 can perform the coordinate detecting operation by performing the processing operations as shown in the flowcharts of FIGS. 11 to 20 described above. Among the coordinate detection operations described above, the X and Y direction scanning operations can perform processing operations corresponding to the structures of the two types of liquid crystal display devices 51 and 61, respectively. Either of the methods can be selected and implemented. As a result, four types of processing operations can be performed. These four
The types of processing operations include an arithmetic operation of the central processing circuit 37, a signal transmitting / receiving operation of the interface circuit 41, and a timer 3
Since the timing operations of the eight are performed in combination, the tablet control circuit 32 can be shared. Therefore, if only a single tablet control circuit 32 shown in FIG. 1 is prepared, four types of processing operations can be performed.

These processing operations are so-called software processing, and are realized by the central processing circuit 37 executing a program of the processing operation stored in the memory 39. Therefore, by storing a program of a processing operation corresponding to the structure of another liquid crystal display device 28 and a processing operation including another scanning method in the memory 39, the tablet structure of the tablet detection circuit 32 can be changed without changing the circuit structure. And a processing operation corresponding to another scanning method can be performed. Also, at this time, it is only necessary to add a new program to the memory 39, so that there is no need to change the circuit structure in accordance with the structure of the liquid crystal display device 28 unlike the conventional tablet control circuit. Therefore, when the structure of the liquid crystal display device 28 used for the display detection device 24 is changed, the design of the device 28 can be easily changed. Further, since the circuit structure of the tablet control circuit 32 becomes independent of the structure of the liquid crystal display device 28, the control circuit 32 having the same structure can be replaced with a liquid crystal display device having a plurality of types of structures by simply changing the above-described program. 28 can be used for the display detection device 24. Therefore, the versatility of the display detection device 24 itself can be improved.
As described above, by performing the coordinate detection operation by so-called software control, the expandability of the tablet detection circuit 3 can be improved. The tablet control circuit 32
The circuit components 35 to 44, the liquid crystal display device 28, and the lighting device 29 therein can be realized by existing general-purpose devices.

Also, in the electronic device 21 of FIG. 1, a central processing circuit 37 is provided separately from the central processing circuit 26 of the host device 23.
A tablet control circuit 32 including a memory 39, a memory 39, and an interface circuit 41 is prepared, and the control circuit 32 executes a coordinate detection operation. As described above, the electronic device 21 is divided into a central processing circuit 26 of the host device 23 which is a main system which performs a processing operation of the entire electronic device 21 and a central processing circuit 26 of a tablet control circuit 32 which is a subsystem which performs arithmetic processing of the coordinate detection operation. By separating it into the processing circuit 37, the load on the host device 23 is reduced,
A decrease in the throughput of the processing operation of the central processing circuit 26 can be prevented. In addition, by performing such separation, the processing operation of the entire electronic device 21 and the coordinate detection operation can be performed in parallel, so that the processing time required for the processing operation of the entire electronic device 21 can be reduced. Conversely, the central processing circuits 26 and 37 may be realized by a single arithmetic circuit.

In the Y coordinate scanning operation, the unit time can be changed. The unit time is calculated as shown in FIG.
When the time is set to be shorter than the processing operations of steps d10 to d13, the maximum coordinate value obtained by the Y coordinate is larger than the number of Y coordinate electrodes. Thereby, the display detection device 2
The apparent resolution of the Y coordinate set to 4 can be made larger than the actual resolution set by the number of Y coordinate electrodes. Therefore, for example, when the host device 23 automatically acquires the apparent resolution as the resolution of the display detection device 24, a resolution higher than the actual resolution of the display detection device 24 is automatically set in the host device 23. be able to. The numerical value representing the Y coordinate is
Since it corresponds to the apparent resolution, the host device 23
When performing the arithmetic processing using the coordinates, there is no need to perform the arithmetic processing for making the value of the Y coordinate correspond to the apparent resolution, and the processing operation is easy.

When the apparent resolution is increased, the Y coordinate obtained is such that the Y coordinate electrodes are virtually arranged between the Y coordinate electrodes of the panel members 52; Can be regarded as coordinates specified using a virtual liquid crystal display device having a virtual panel member.
Within the area occupied by one Y coordinate electrode of the actual panel member 52; 62, 63, the virtual panel member has one real Y coordinate electrode.
A coordinate electrode 57 and a plurality of virtual Y coordinate electrodes are arranged,
A certain value of the Y coordinate corresponds to each coordinate electrode. At this time,
In the Y coordinate acquisition operation in step d15 described above, in addition to the Y coordinate obtained as the quotient of Equation 1, the Y coordinate
The Y coordinate of the virtual Y coordinate electrode around the coordinate electrode is also acquired.
This allows you to increase the apparent resolution,
The area occupied by the acquired Y coordinate and the area occupied by the coordinate electrode that is actually electrostatically coupled to the indicator electrode can be made to match. Therefore, the Y coordinate in the area desired by the operator of the device 21 can be reliably obtained.

Further, for example, a deviation of less than the processing time required for detecting an instruction signal for a single coordinate electrode from when the specific coordinate electrode and the instruction electrode are electrostatically coupled to when the instruction signal is derived is obtained. If this occurs and the apparent resolution has not been increased, the division of Equation 1 above will have a remainder. When the remainder is rounded off, the obtained Y coordinate may be shifted from the Y coordinate of the specific coordinate electrode by a shift width of one Y coordinate electrode. When the apparent resolution is increased in the above case, the Y coordinate obtained as the quotient of the above equation 1 indicates the Y coordinate between the Y coordinate of the specific coordinate electrode and the coordinate electrode adjacent to the specific coordinate electrode, The deviation width of the Y coordinate that is shifted when the remainder is rounded is smaller than the deviation width of one Y coordinate electrode. From these facts, the obtained Y-coordinate represents between the Y-coordinate of the specific coordinate electrode and the Y-coordinate of the Y-coordinate electrode adjacent to the specific coordinate electrode. Therefore, when the apparent resolution is increased, the deviation of the Y coordinate due to the delay of the instruction signal can be reduced. Therefore, it is possible to prevent the central processing circuit 37 from erroneously recognizing the Y coordinate electrode actually electrostatically coupled as the next coordinate electrode after the Y coordinate electrode. Therefore, the accuracy of the detected coordinates can be improved.

Also, in the processing operation of the X-direction scanning method shown in the flowcharts of FIGS. 14 and 15, if the unit time used for the calculation of the X coordinate detection is shorter than the time required for the processing of steps e10 to e12, the Y coordinate Similarly, the apparent resolution and accuracy of the X coordinate can be improved.

Further, when the deviation between the X and Y coordinates is small as described above, for example, in the character recognition operation performed by the host device 23, the designated point designated by the operator of the electronic device 21 can be reliably recognized. It is possible to prevent the relative position from being shifted from the designated point designated before the designated point. For example, it is possible to prevent the X and Y coordinates from being discontinuous when two adjacent points are designated, or to prevent the X and Y coordinates from continuing when two distant points are designated. Therefore, it is possible to prevent a point from being mistakenly recognized as a line and a point from being mistakenly recognized as a line, thereby preventing an error in character recognition.

FIG. 21 is a block diagram showing an electrical configuration of an electronic device 111 including the display detection device 24 according to the second embodiment of the present invention. The electronic device 111 is a device similar to the electronic device 21 of the first embodiment. Only the structure of the interface circuit is different, and the structure of other components and the behavior of all components are the same. The description of the same components having the same structure is omitted.

The interface circuit 113 has a configuration similar to that of the interface circuit 41 shown in FIG.
Except that the other structures are equal. The interface circuit 113 includes a switching circuit 4 outside the circuit.
By transmitting and receiving signals to and from the register group 2, various signals are stored in the register group 43, similarly to the interface circuit 41. The signal output from the interface circuit 113 is provided to the liquid crystal display device 28 via the switching circuit 42. Further, the display control signal from the display control circuit 31 is supplied to the switching circuit 42, then stored in the register group 43 in the interface circuit 113, and supplied to the liquid crystal display device 28.

Display control circuit 31 and liquid crystal display device 28
When the signal transmission / reception speed becomes higher than that of the conventional circuit 31 and the device 28, the signal transmission / reception speed of the tablet control circuit 112 also needs to be increased. Since the data bit length of the data signal of the liquid crystal display device 28 changes according to the structure of the liquid crystal display device 28,
The output terminal of the data signal of the tablet control circuit 112 is
It is necessary to design according to this data bit length. The switching circuit 42 is a component of the tablet control circuit 112 whose design needs to be changed according to the transfer speed and the output terminal structure. Therefore, by separating the switching circuit 42 from the interface circuit 113, when the display control circuit 31 and the liquid crystal display device 28 are changed, only the structure of the switching circuit 42 is changed without changing the interface circuit 113. Thus, the tablet control circuit 112 corresponding to the changed circuit 31 and the device 28 can be obtained. Therefore, the design of the tablet control circuit 112 can be easily changed.

The electronic device 11 is similar to the electronic device 21.
By integrating the circuit components in the tablet control circuit 112 even in the case of 1, the number of components of the control circuit 112 can be reduced, and the manufacturing cost can be reduced. At this time, the switching circuit 42 as well as the determination circuit 35
It is preferable not to have the built-in 15. Thus, when the design of the tablet control circuit 112 is changed as described above, the design change of the control circuit 112 can be performed without performing the circuit design of the integrated circuit 115, so that the design change is further facilitated. . In addition, when the switching circuit 42 is not provided, the integrated circuit 1 is not provided.
Fifteen terminals can be reduced. Therefore, for example, even when the number of terminals of the integrated circuit 115 is limited,
It is preferable that the switching circuit 42 is not built in the integrated circuit 115.

Although the electronic devices 21 and 111 have been described using the simple matrix type liquid crystal display device 28, the liquid crystal display device 28 may be an active matrix type liquid crystal display device. In an active matrix liquid crystal display device, a plurality of pixel electrodes are arranged in a matrix on one substrate surface in a panel member, and a uniform counter electrode is arranged on the other substrate surface. Therefore, among these pixel electrodes, Y
A group of pixel electrodes arranged in parallel in the direction is regarded as a single X coordinate electrode, and a group of pixel electrodes arranged in parallel in the X direction is regarded as a single Y coordinate electrode. When the voltage is applied, the coordinate detection operation can be performed by the same processing operation as the flowcharts of FIGS. 11 to 20 described above. Further, instead of the liquid crystal display device 28, a display device including a substrate member of the same type as the simple matrix type and the active matrix type and having another display medium may be used. For example, an EL display device using an electroluminescence light emitting layer as a display medium may be used. Further, a display device using another display medium may be used.

The above-described tablet control circuit 112
May be used not only for a display-integrated tablet device but also for a tablet device that performs only a coordinate detection operation. Furthermore, the above-described coordinate detection operation is not limited to the electrostatically coupled tablet device, and may be implemented by an electromagnetically coupled tablet device. In the electromagnetic coupling type tablet device, an electrode member is prepared by removing the liquid crystal layer from the panel members 52; 62, 63 of the above-mentioned liquid crystal display devices 51, 61, and an electromagnetic field is generated at the tip of the pen member. Any X in
Then, it is electromagnetically coupled with the Y-coordinate electrode to detect an induced voltage induced in the X- and Y-coordinate electrodes. At this time, the determination of whether or not the induced voltage is generated is sequentially performed by sequentially detecting the voltage values of all the X and Y electrodes. The above-described elapsed time is a time from the start of the operation of detecting the voltage values of the X and Y coordinate electrodes to the detection of the induced voltage.

As described above, if the tablet device obtains coordinate values by sequentially detecting the voltage values of a plurality of electrodes arranged in a matrix or on a straight line, a tablet device other than the electrostatic coupling type and the electromagnetic coupling type can be used. The tablet device described above may use a coordinate detection method using the above-described time scanning method. For example, a digital resistive liquid crystal display device may be used.
When the coordinate detection operation of the time scanning method is performed on these tablet devices, the accuracy of the detected coordinates can be improved, and the apparent resolution can be further increased.

[0169]

As described above, according to the present invention, the coordinate detecting device is a so-called electrostatic coupling type or electromagnetic coupling type tablet device. In this device, an operation of generating a selection control signal for selecting a specific coordinate electrode and an operation of detecting the coordinates of a coordinate point are performed by arithmetic processing. by this,
Since the control circuit, which is a large-scale circuit having a large number of gates, can be deleted from the coordinate detection device, the circuit structure of the entire coordinate detection device can be simplified. Therefore,
The size of the coordinate detecting device can be reduced, and the manufacturing cost can be reduced. In the coordinate detection operation, the coordinates are obtained by an arithmetic process using the elapsed time and the unit time. At this time, if the unit time is set to a value less than a predetermined time period, the apparent resolution of the coordinate detection device can be improved. This also makes it possible to improve the accuracy of the obtained coordinate values as compared with the coordinate detection device of the related art.

Further, according to the present invention, the above-mentioned coordinate detecting device is an electrostatic coupling type tablet device, and scans all coordinate electrodes by a scanning signal to charge the specific coordinate electrodes. In this case, the circuit structure of the coordinate detection device can be simplified by performing the operation of generating the selection control signal and the operation of detecting the coordinate of the coordinate point as described above.

Further, according to the present invention, the unit time used in the coordinate detecting operation of the coordinate detecting device can be changed. This makes it possible to arbitrarily change the apparent resolution of the coordinate detection device.

Further, according to the present invention, the above-described coordinate detecting device has a plurality of types of arithmetic processing for generating the selection control signal and arithmetic processing for the coordinate detecting operation. Either one is implemented according to. This eliminates the need for the coordinate detection device to change the structure of the coordinate detection device when the configuration of the selection means and the arrangement of the coordinate electrodes are changed. Therefore, it is possible to easily change the design of the selecting means and the coordinate electrode as compared with the coordinate detection device of the related art. Further, since the selection means and the arrangement of the coordinate electrodes to be used can be arbitrarily selected, the versatility of the coordinate detection device can be improved. further,
Since the plurality of processes are arithmetic processes, the number of gates of the circuit does not increase even if the number of processes prepared in advance is increased.
Therefore, the versatility of the coordinate calculation device can be improved without increasing the circuit scale.

Further, according to the present invention, the above-described coordinate detecting device is a so-called display-integrated tablet device, and the substrate member also serves as a part of a panel member for a display operation. In such a coordinate detection device, the display control signal and the detection control signal are periodically and alternately switched by the switching unit and applied to the voltage application unit, and the display operation and the coordinate detection operation are periodically performed in a time-division manner. . By performing the signal generation operation and the coordinate detection operation by arithmetic processing in such a display-integrated tablet device, the circuit scale of the device can be reduced. Further, by adopting a structure in which an induced voltage is induced in the indicator electrode as in claim 2, the selecting means added to the panel member of the display device can be used as it is.

Further, according to the present invention, the switching time period of the switching means can be changed in accordance with the display control signal and the configuration of the selecting means. Therefore, the coordinate detecting device can arbitrarily select the selection means and the arrangement of the coordinate electrodes to be used, so that the versatility of the coordinate detecting device can be improved. Further, since this switching time period is determined by the arithmetic processing of the switching control means, it can be changed without changing the circuit structure of the coordinate detecting device. Therefore, it is possible to easily change the design of the coordinate detecting device. Further, since the switching time period is determined by the arithmetic processing, it is not necessary to provide a plurality of electric circuits in advance as in the conventional coordinate detection device. Therefore, the circuit scale of the coordinate detecting device can be reduced as compared with the conventional coordinate detecting device.

Further, according to the present invention, of the above-described coordinate detecting devices, four means of the selection control signal generating means, the coordinate detecting means, the timing means, and the signal switching means, or the signal switching means are excluded from the four means. These three means are integrated to form an integrated circuit. As a result, the number of components of the entire coordinate detecting device is reduced, so that the structure of the coordinate detecting device can be simplified. Therefore, the size of the coordinate detecting device can be further reduced, and the manufacturing cost can be further reduced. Furthermore, when three means except the signal switching means are integrated, the number of terminals of the integrated circuit can be reduced as compared with the case where four means are integrated. Further, a coordinate detecting device using an integrated circuit in which three means are integrated can improve the versatility of the device as compared with a coordinate detecting device using an integrated circuit in which four means are integrated.

Further, according to the present invention, signal generation control means,
The selection control signal generating means and the coordinate detecting means are realized by the arithmetic processing of the same arithmetic circuit. According to the present invention,
The selection control signal generating means and the coordinate detecting means are realized by the arithmetic processing of the same arithmetic circuit. Thereby, the circuit structure of the coordinate detecting device can be further simplified. Therefore, when a part of the coordinate detecting circuit is integrated, it can be more easily integrated. In addition, since the signal generation control means and the arithmetic circuits of the other two means are separate circuit components, the load on the signal generation control means can be reduced, and the throughput of the means can be prevented from being reduced. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of an electronic device 21 including a coordinate detection device according to a first embodiment of the present invention.

FIG. 2 is a plan view illustrating a detailed structure of a liquid crystal display device 51 having a single panel structure.

FIG. 3 is a plan view illustrating a detailed structure of a liquid crystal display device 61 having a dual panel structure.

FIG. 4 is a block diagram illustrating a specific structure of a switching circuit 42.

FIG. 5 is a schematic diagram showing a specific structure of a data register 91.

FIG. 6 shows a specific structure of a control register 92 and each bit b.
It is a schematic diagram which shows the signal which 0-b7 represents.

FIG. 7 is a schematic diagram showing a specific structure of a command register 93 and signals represented by bits b0 to b7.

FIG. 8 is a schematic diagram showing a specific structure of a status register 94 and signals represented by bits b0 to b7.

FIG. 9 is a schematic diagram showing a specific structure of a flag register 95 and signals represented by bits b0 to b7.

FIG. 10 is a schematic diagram showing a specific structure of a model register 96 and signals represented by bits b0 to b7.

FIG. 11 is a block diagram schematically showing a main processing operation performed by a central processing circuit 37.

12 is a flowchart schematically illustrating a coordinate detection operation of the central processing circuit 37 performed in step a4 of the main processing operation of FIG. 11;

FIG. 13 is a step c3 in the coordinate detecting operation of FIG. 12;
5 is a flowchart for explaining in detail a Y-direction scanning operation of the central processing circuit 37 performed in FIG.

14 is a step c5 in the coordinate detecting operation of FIG.
6 is a flowchart for explaining in detail the X-direction scanning operation of the central processing circuit 37 performed in FIG.

FIG. 15 is a step c5 in the coordinate detecting operation of FIG. 12;
6 is a flowchart for explaining in detail the X-direction scanning operation of the central processing circuit 37 performed in FIG.

FIG. 16 is a schematic diagram illustrating a data signal output in an X-direction scanning operation when the data bit length of the liquid crystal display device is 4 bits.

FIG. 17 is a schematic diagram illustrating a data signal output in an X-direction scanning operation when the data bit length of the liquid crystal display device is 8 bits.

FIG. 18: Step e in the flowchart of FIGS. 14 and 15
It is a flowchart for demonstrating the write operation of the data signal in 9, e18, e32, and e43.

FIG. 19 is a flowchart illustrating a command processing operation of the central processing circuit 37 performed in step a6 of the flowchart of the main control operation in FIG. 11;

20 is a flowchart for explaining a command processing operation of the central processing circuit 37 performed in step a6 of the flowchart of the main control operation in FIG. 11;

FIG. 21 is a block diagram illustrating an electrical configuration of an electronic device 111 including a coordinate detection device according to a second embodiment of the present invention.

FIG. 22 is a block diagram illustrating an electrical configuration of a coordinate detection device 1 according to the related art.

[Explanation of symbols]

 21, 111 Electronic device 23 Host device 24 Display detection device 26, 37 Central processing circuit 28, 51, 61 Liquid crystal display device 31 Display control circuit 32, 112 Tablet control circuit 34 Pen member 35 Judgment circuit 38 Timer 41, 113 Interface circuit 42 switching circuit 43 register group 46,115 integrated circuit 48 signal generation unit 49 coordinate detection unit 50 switching control unit 52 panel member 53 X coordinate electrode control circuit 54 Y coordinate electrode control circuit 56 X coordinate electrode 57 Y coordinate electrode 62 first panel Member 63 Second panel member 64 First X coordinate electrode control circuit 65 Second X coordinate electrode control circuit 66 First Y coordinate electrode control circuit 67 Second Y coordinate electrode control circuit

Claims (10)

[Claims] 1. A plurality of coordinate electrodes arranged along a coordinate axis on a flat substrate surface on which a predetermined coordinate axis is set, and one of the plurality of coordinate electrodes movable near the substrate. A selection electrode for electrostatically or electromagnetically coupling with the coordinate electrode of the first position, and a selection control signal generating means for generating a selection control signal for sequentially selecting a specific coordinate electrode from among the plurality of coordinate electrodes by a first arithmetic processing In response to the selection control signal, selecting means for sequentially selecting a specific coordinate electrode at a predetermined time period, and voltage detecting means for detecting an induced voltage induced in the specific coordinate electrode or the indication electrode. A time measuring means for measuring an elapsed time from when the selecting means starts to select the specific coordinate electrode to when the voltage detecting means detects the induced voltage, based on the elapsed time and the time period. And a coordinate detecting means for detecting a coordinate point of a specific coordinate electrode electrostatically or electromagnetically coupled on the coordinate axis from a predetermined unit time by a second arithmetic processing. apparatus. 2. The method according to claim 1, wherein the selection unit generates a scan signal for scanning the specific coordinate electrode based on the selection control signal generated by the selection control signal generation unit, and supplies the scan signal to each of the coordinate electrodes. The coordinate detecting device according to claim 1, wherein: 3. The coordinate detecting device according to claim 1, wherein the unit time is changeable. 4. The method according to claim 1, wherein the first and second calculation processes include a configuration such as a number of input terminals of the voltage detection means and a signal transmission / reception speed.
The coordinate detecting device according to claim 1, further comprising a plurality of processes corresponding to an arrangement of the plurality of coordinate electrodes, and selecting and executing one of the plurality of processes. 5. The coordinate electrode is a strip-shaped electrode, the two substrates are provided, and a panel member having a rectangular coordinate system is formed including the coordinate electrode, and the panel member has one surface. The coordinate electrodes include two substrates each arranged in parallel with each other, at a predetermined interval so that the longitudinal direction of the coordinate electrodes of each substrate is orthogonal, and one surface is disposed to face, Further, a display medium whose display characteristics change in accordance with whether or not a pair of opposing coordinate electrodes are scanned is a panel member sandwiched between two substrates, and the coordinate detection device includes: Display control signal generating means for generating a display control signal for selectively changing the display characteristics of a display medium interposed between the coordinate electrodes; a display control signal generated by the display control signal generating means; and the selection control. Signal generation means Switching means for alternately switching the generated selection control signal with a switching time period determined by a predetermined cycle calculation process and providing the switching control signal to the selection means, wherein the selection means is provided with a display control signal. 3. The coordinate detecting device according to claim 2, wherein a scanning signal for scanning each of the opposing coordinate electrodes is generated based on a display control signal and is provided to each of the coordinate electrodes. 6. The switching time period can be changed in accordance with the display control signal generated by the display signal generation means, the number of input terminals of the selection means, the signal transfer speed, and the like. The coordinate detecting device according to claim 5, wherein 7. The apparatus according to claim 7, wherein said selection control signal generating means, said coordinate detecting means, said switching means, and said time measuring means
The coordinate detecting device according to claim 5, wherein a single integrated circuit is formed. 8. The coordinate detecting device according to claim 1, wherein a single integrated circuit is formed by said selection control signal generating means, said coordinate detecting means and said time measuring means. 9. The apparatus further includes signal generation control means for controlling the selection control signal generation means so as to generate the selection control signal, wherein the signal generation control means, the selection control signal generation means, and the coordinate detection means 2. The coordinate detecting device according to claim 1, wherein a single arithmetic circuit is formed. 10. The coordinate detecting device according to claim 1, wherein a single arithmetic circuit is formed by said selection control signal generating means and said coordinate detecting means.