Coordinate input device

Abstract: The present invention concerns a coordinate input device for entering coordinate values by superposing on a display device (LCD or CRT). The device is comprised of a coordinate input section (401) wherein a first conductive sheet (151) for x-coordinate detection provided with electrodes (x1, x2) on a pair of end edges and a second conductive sheet for y-coordinate detection provided with electrodes on a pair (152) of end edges are superposed through a spacer (153) so that respective electrodes intersect orthogonally. A predetermined voltage is applied between one of the electrodes of said first conductive sheet and one of electrodes of said second conductive sheet for detecting the variation of said voltage. When the voltage varies, a predetermined voltage is applied between one electrode (x1) of the first conductive sheet and one electrode (y2) of the second conductive sheet. When the voltage does not vary, no current flows between the pair of electrodes (x1, x2 or y1 or y2) of either of the first conductive sheet or the second conductive sheet. Therefore the low power consumption is maintained.

Description: Field of Invention: The present invention concerns a coordinate input device appropriate for superposing coordinates on a LCD (or CRT) display device or others. Description of the Prior Art: Among coordinate input devices of the prior art, a device including the composition of the touch panel (input panel) as coordinate input section as shown in Fig. 26 is well-known. In this composition, a first conductive sheet 151 for x-coordinate detection provided with electrodes x1 and x2 on a pair of end edges and a second conductive sheet 152 for y-coordinate detection provided with electrodes y1 and y2 on a pair of end edges are superposed through a spacer 153 so that respective electrodes x1, x2 and y1, y2 intersect orthogonally. The first conductive sheet 151, the second conductive sheet 152 and the spacer 153 are all transparent. Under the first conductive sheet 151, a screen such as LCD (or CRT) display devices or others is disposed through a insulator plate composed of a transparent glass plate or reinforced plastic. As for said spacer 153, transparent aeolotropic conductive rubber sheet, lattice member or conveniently perforated sheet may be adopted. In normal state, the spacer 153 isolates the first conductive sheet 151 and the second conductive sheet 152, however, when it is compressed by an input pen or others, it acts for conducting the first conductive sheet 151 and the second conductive sheet 152. The electric composition of said coordinate input device is as shown in Fig. 28. In other words, in this composition, an A/D converter 204 is connected to a touch panel 201 constituting the coordinate input section through a switch for changing the coordinate axis to be detected. An x/y control section 203 is connected to a CPU 205 so as to allow to direct change-over of respective switches 202-1 to 202-3 of a switch section 202. The switch 202-1 of the switch section 202 is a switch for change-over so as to supply one of the electrodes y2. x2 with voltage VCC, the switch 201-2 is a switch for change-over so as to supply one of the electrodes y1, x1 with earth potential and the switch 202-3 is a switch for change-over so as to supply the A/D converter 204 with one of the coordinate value of x-coordinate or y-coordinate. In response to the direction form the CPU 205, the x/y control section 203 changes over respective switches 202-1 to 202-3 of the switch section 202 through a signal line 208. This Fig. 28 shows that the respective switches 202-1 to 202-3 are changed over so as to permit to detect the coordinate value of y-coordinate. In said coordinate input device, as shown in Fig. 26. when a point p is pressed by an input pen or else, a current flowing to the electrode y2 by a voltage VCC is directed to the corresponding position of the first conductive sheet 151 from the point p and then to the A/D converter 204 flowing to the direction of the electrode x1. Here, y direction voltage Vy of the point p is given by the following expression: Vy=(VCC x R1)/(R1 + R2) where R1 is the resistance value between the electrode y1 and the point p on the second conductive sheet 152 and R2 is the resistance value between the electrode y2 and the point p on the second conductive sheet 152. Signals directed by the A/D converter 204 correspond to the voltage Vy of said point p, y-coordinate value of the point p may be obtained considering the voltage drop due to the first conductive sheet 151. For instance, y-coordinate value may be obtained easily by providing the CPU 205 with a table for correlating the output value of the A/D converter 204 when respective points of the touch panel 201 are operated and y coordinate values, x coordinate values also may be obtained easily by providing a similar table. However, there was an inconvenience in that, as the voltage VCC is applied to the electrode y1 on the second conductive sheet 152 and the electrode y2 is supplied with earth potential even when there is no input operation, current flows between the electrodes y1 and y2 as shown by arrows in Fig. 27 so as to consume power. It would not provoke a problem when the power is securely supplied from a power source as in cash dispenser (CD) of a bank, for instance, however it provoke a critical difficulty for a device working on batteries as mobile terminals. US-5,266,750 describes a tablet input device that is constructed so that the current flowing during an input waiting period is reduced. The described tablet input device has two resistance sheets slightly spaced from each other by a spacer, so that they are in a non-contacting state when a pen, finger or the like is not placed on to the upper resistance sheet. In order to reduce the current flowing during the input waiting period, a diode and a pull-down resistor are used, where the diode sets the voltage level of one of the resistance sheets to a high level, while the whole surface of the other resistance sheet is set to a low voltage by the resistor. When the upper resistance sheet is pressed downwards under this condition, the two sheets are brought into contact at the pressed point, which leads to the sheet having a low voltage level being pulled up to the high level. Consequently, a voltage change can be detected. Voltages detected at either of the two resistance sheets are fed into an A/D converter, which in turn provides digital values to a CPU. Another coordinate input device using a pair of transparent electrodes is known from EP 05 41 102 A1. US-A-5,367,130, which represents the basis for the preamble of claim 1, describes a graphics tablet having a double layer basic structure. The graphics tablet has two members, a top layer and a bottom layer. These layers are coated with resistive material, respectively, and separated by a small distance, such that no contact exists between the two layers in a stand-by state. Only when a stylus is pressed on the top layer, contact can be achieved. Then the position of the stylus is measured by applying current on the one sheet and measuring the voltage on the other sheet. A microprocessor detects that a stylus has made contact with the tablet of the basis of a signal on a line. The signal on this line is at ground level when no stylus is applied, and goes above ground level, when a stylus is applied. The transition on the line causes an interrupt to occur in the microprocessor. In response to this interrupt, the stylus position is read. and tracked on the basis of the output of an A/D converter. During the tracking process, it is permanently detected whether the stylus is down. Disclosure of the Present Invention: The first object of the present invention is to provide a coordinate input device reducing useless power consumption and appropriate to be applied to mobile terminals. The second object of the present invention is to provide a coordinate input device for responding appropriately to the coordinate input operation to obtain necessary coordinate values. The third object of the present invention is to provide a coordinate input device which shifts to the low power consumption mode when the coordinate input operation is not made for a predetermined period of time. The fourth object of the present invention is to provide a coordinate input device which may be attached to the screen of a display device and may be used as a device for indicating a position on the screen or the like. The fifth object of the present invention is to provide a coordinate input device which may be attache to the screen of a cellular telephone display device for using as a device for indicating a position on the screen or the like. The sixth object of the present invention is to provide a coordinate input device which may be attache to the screen of the display device of a cellular telephone provided with character input function for using as a device for indicating a position on the screen or the like. These objects are achieved by a coordinate input device having the features of claim 1. Advantageous embodiments are described in the dependent claims. The coordinate input device of the present invention comprises a coordinate input wherein a first conductive sheet for x-coordinate detection provided with electrodes on a pair of end edges and a second conductive sheet for y-coordinate detection provided with electrodes on a pair of end edges are superposed through a spacer so that respective electrodes intersect orthogonally and a mode control means for shifting to coordinate input reception mode by applying a predetermined voltage between one of electrodes of said second conductive sheet and detecting the variation of said voltage. Thus, a predetermined voltage is applied between one of electrodes of the first conductive sheet and one of electrodes of the second conductive sheet and these electrodes are insulated by a spacer. In other words, for both of the first conductive sheet and the second conductive sheet, current does not flow between a pair of electrodes disposed thereon and set in a stand-by state (mode) of low power consumption. In this stand-by mode, it is possible to detect any input by monitoring the variation of the predetermined voltage applied between one of electrodes of the first conductive sheet and one of electrodes of said second conductive sheet. Moreover, the coordinate input device of the present invention comprises a selection means for selecting the signal from one of the first conductive sheet and the second conductive sheet, a central control section for loading the coordinate value through this selection means, a stand-by control section for selectively applying a predetermined voltage between both electrodes of said first conductive sheet or both electrodes of said second conductive sheet or applying a predetermined voltage between one of electrodes of said first conductive sheet and one of electrodes of said second conductive sheet based on the direction from this central control section and a logic circuit for transmitting the variation of the predetermined voltage to said central control section when a predetermined voltage is applied between one of electrodes of said first conductive sheet and one of electrodes of said second conductive sheet by this stand-by control section, wherein said central control section shifts to a mode for loading the coordinate value when the variation of the predetermined potential is detected by this logic circuit. Thus, the central control section detects the variation of the predetermined potential by the logic circuit when a predetermined voltage is applied between one of electrodes of said first conductive sheet and one of electrodes of said second conductive sheet, of which period of time corresponding to the low power consumption state. When a variation appears on the predetermined voltage output from the logic circuit, in order to load the coordinate value, the central control section directs the stand-by control section to apply a predetermined voltage between both electrodes of said first conductive sheet or both electrodes of said second conductive sheet and shifts to the coordinate value loading mode. When a coordinate value is not input within a predetermined period of time, a predetermined voltage is applied between one of electrodes of said first conductive sheet and one of electrodes of said second conductive sheet, it shifts to the low power consumption state without flowing any current between the pair of electrodes both on the first conductive sheet and the second conductive sheet. On the other hand, during the stand-by state during which the central control section detects the variation of the predetermined voltage by the logic circuit, if coordinate is input, said predetermined voltage changes and is detected, then predetermined voltage is applied to between the both electrodes of the first conductive sheet or between the both electrodes of the second conductive sheet so as to shift a mode capable of detecting the coordinate value. Moreover, by working in low power consumption mode during the variation of the predetermined voltage is detected by the logic circuit, and in normal operation mode for loading the coordinate value, useless power consumption is prevented. Brief Description of Drawings: Fig. 1 is a composition diagram showing the normal processing mode of the coordinate input device according to an embodiment of the invention. Fig. 2 is a composition diagram showing the stand-by mode of the coordinate input device according to an embodiment of the invention. Fig. 3 is a composition diagram showing the normal processing mode by the coordinate input section of the coordinate input device according to an embodiment of the invention. Fig. 4 is a composition diagram showing the stand-by mode by the coordinate input section of the coordinate input device according to an embodiment of the invention. Fig. 5 is a flowchart showing the operation of the coordinate input device according to an embodiment of the invention. Fig. 6 is a front view of a cellular telephone to which the coordinate input device according to an embodiment of the invention is applied. Fig. 7 is a composition diagram showing a cellular telephone to which the coordinate input device according to an embodiment of the invention is applied. Fig. 8 is a composition diagram of a character input device to which the coordinate input device according to an embodiment of the invention is applied. Fig. 9 is a composition diagram showing a key matrix portion, essential part of the character input device shown in Fig. 8. Fig. 10 is a composition diagram showing an input control section, essential part of the character input device shown in Fig. 8. Fig. 11 is a composition diagram showing a memory table included in the input control section, essential part of the character input device shown in Fig. 8. Fig. 12 is a flowchart for illustrating the operation of the input control section, essential part of the character input device shown in Fig. 8. Fig. 13 is a composition diagram showing a display control section, essential part of the character input device shown in Fig. 8. Fig. 14 is a composition diagram showing a dictionary retrieval section, essential part of the character input device shown in Fig. 8. Fig. 15 is a schematic diagram showing a dictionary. essential part of the character input device shown in Fig. 8. Fig. 16 is a concrete composition diagram showing the dictionary, essential part of the character input device shown in Fig. 8. Fig. 17 is a concrete composition diagram showing the dictionary, essential part of the character input device shown in Fig. 8. Fig. 18 is a concrete composition diagram showing the dictionary, essential part of the character input device shown in Fig. 8. Fig. 19 is a flowchart for illustrating the operation of the dictionary retrieval section, essential part of the character input device shown in Fig. 8. Fig. 20 is a diagram for illustrating the input operation using the character input device shown in Fig. 8. Fig. 21 is a diagram for illustrating the dictionary retrieval by the input operation using the character input device shown in Fig. 8. Fig. 22 is a composition diagram of a character input device composed by applying the coordinate input device according to an embodiment of the invention. Fig. 23 is a flowchart for illustrating the operation of the dictionary retrieval section, essential part of a character input device composed by applying the coordinate input device according to an embodiment of the invention. Fig. 24 is a composition diagram of a memory table included in the dictionary retrieval section, essential part of the character input device shown in Fig. 23. Fig. 25 is a diagram illustrating a display example of a character input device composed by applying the coordinate input device according to an embodiment of the invention. Fig. 26 is a composition diagram showing the coordinate input section of a coordinate input device according the prior art. Fig. 27 is a composition diagram showing the stand-by mode of the coordinate input section of a coordinate input device according to the prior art. Fig. 28 is a composition diagram of a coordinate input device according to the prior art. Detailed Description of the invention: Fig. 1 is a composition diagram showing the coordinate input device according to an embodiment of the invention. The coordinate input device according to the embodiment is comprised of a CPU (central control section) 405 for integrally controlling this device and for obtaining the coordinate value, a touch panel section 401 constituting the coordinate input section, a switch section 402 for changing over the coordinate detection mode of y-axis and the coordinate detection mode of x-axis of this touch panel section 401, an x/y control section 403 for changing over this switch section 402 based on the instruction supplied by said CPU 405, a switch section 406 for changing the voltage to be supplied to the touch panel section 401, a stand-by control section 407 for changing over this switch section 406 based on the instruction supplied by said CPU 405, an A/D converter 404 for loading the coordinate value of y-coordinate or the coordinate value of x-coordinate of the touch panel section 401 and a logic circuit 410 for communicating the variation of the predetermined voltage by the input operation of the touch panel 402. Said touch panel section 401 is composed as shown in Fig. 3. In this composition, a first conductive sheet 151 for x-coordinate detection provided with electrodes x1 and x2 on a pair of end edges, and a second conductive sheet 152 for y-coordinate detection having electrodes y1 and y2 on a pair of end edges are superposed through a spacer 153 so that respective electrodes x1, x2 and y1, y2 intersect orthogonally. The first conductive sheet 151, the second conductive sheet 152 and the spacer 153 are all transparent. Under the first conductive sheet 151, a screen such as LCD (or CRT) display devices or others is disposed through a insulator plate composed of a transparent glass plate or reinforced plastic. As for said spacer 153, transparent aeolotropic conductive rubber sheet, lattice member or conveniently perforated sheet may be adopted. In normal state, the spacer 153 isolates the first conductive sheet 151 and the second conductive sheet 152, however, when it is compressed by an input pen or others, it acts for electrically conducting the first conductive sheet 151 and the second conductive sheet 152. In said coordinate input section, the electrode x2 of the first conductive sheet 151 and the electrode y2 of the second conductive sheet 152 are connected to a switch 402-1 of the switch section 402. and the electrode x1 of the first conductive sheet 151 and the electrode y1 of the second conductive sheet 152 are connected to a switch 402-2 and a switch 402-3 or the switch section 402. On the other hand, the switch section 406 includes a switch 406-1 for changing over to supply the switch 402-1 directly with the power VCC or to supply the switch 402-1 with the power VCC through a pull-up resistor, and a switch 406-2 for changing over to supply the switch 402-2 or the switch 406-2 of the switch section 402 with earth potential. The logic circuit 410 comprises two inverters 410-1, 410-2 of Schmidt trigger type and is composed to supply the CPU 405 with an interrupt signal of a logic value based on the voltage VCC supplied through the pull-up resistor. Here. the inverter 410-1 is a inverter for chattering prevention and the inverter 410-2 is a inverter for transmitting an interrupt signal of input operation start on the touch panel section 401 by negative logic. In the coordinate input device composed as mentioned above, in the initial state, respective switches of the switch section 402 and the switch section 406 are initially set as shown in Fig. 2. Therefore, the CPU 405 receives H level through the logic circuit 410. The CPU 405 executes the coordinate value loading processing according to the program corresponding to the flowchart shown in Fig. 5. so now the operation will be described based on this. The CPU 405 detects if there is an interrupt of input operation start on the touch panel section 401 by the output from the logic circuit 410. This state corresponds to the stand-by mode and as shown In Fig. 2. the voltage VCC pulled up by the resistor is selected by the switch 406-1 and applied to the electrode y2 of the second conductive sheet 152 through the switch 402-1 and the earth potential is selected by the switch 406-2 and applied to the electrode x1 of the first conductive sheet 151. The state of this stand-by mode is shown in Fig. 4. As obvious from this Fig. 4, both on the first conductive sheet 151 and the second conductive sheet 152, neither voltage VCC nor earth potential are applied between the opposed sheet of the same sheet and no current flows so long as there is no key operation allowing to reduce the power consumption. In Fig. 4, the spacer 153 is omitted. In said stand-by mode, if an input operation is made on the touch panel section 401, as obvious from Fig. 4, current flows to the input point by pulled up voltage VCC applied to the electrode y2, then the current flows to the earth level electrode x1 from the corresponding point on the second conductive sheet 152 through the spacer 153. As a result, the input side potential of the logic circuit 410 decreases to the L level logically and the CPU 405 is supplied with an interrupt signal of negative logic (L level). There, the CPU 405 branches to YES at the step S61 of the flowchart of Fig. 5 for shifting to the normal processing mode(S62). In other words, a stand-by control section 407 is supplied with a change-over instruction signal to the normal processing mode. The s tand-by control section 407 outputs through a signal line 409 a control signal so as to change over the switch section 406 from the state of Fig. 2 to the state of Fig. 1. Thus, the normal processing mode shown in Fig. 1 is provided. In this way, the CPU 405 acts as a mode control means for shifting to the mode accepting the coordinate input (normal processing mode) by applying a predetermined vol-tage VCC between one electrode x1 of the first conductive sheet 151 and one electrode y2 of the second conductive sheet 152, and by detecting the variation of the voltage VCC. By said switching, the voltage VCC is applied directly to the electrode y2 of said second conductive sheet 152 and the earth potential is applied to the electrode y1. Thus, when an operation is made by a input pen or the like on a point p indicated in Fig. 1. a current flowing from the voltage VCC to the electrode y2 is directed from the point p to the corresponding point of the first conductive sheet 151 and then to the electrode x1 before arriving at the A/D converter 404. Here, y direction voltage Vy of the point p is given by the following expression: Vy=(VCC x R1)/(R1 + R2) where R1 is the resistance value between the electrode y1 and the point p on the second conductive sheet 152, and R2 is the resistance value between the electrode y2 and the point p on the second conductive sheet 152. Signals directed to the A/D converter 404 correspond to the voltage Vy of said point p, and y-coordinate value of the point p may be obtained considering the voltage drop due to the first conductive sheet 151. For instance, y-coordinate value may be obtained easily by providing the CPU 405 with a table for correlating the output value of the A/D converter 404 when respective points on the touch panel 401 are operated and y-coordinate values. Then the CPU 405 loads the y-coordinate value (S63), moreever sending the control signal to the x/y control section 403, makes change over the respective switches of the switch section 402 (S64), and loads x-coordinate value (S65). By providing the CPU 405 with a convertion table similar to the case of y-coordinate between the potential and x-coordinate value, x-coordinate value also may be easily obtained. Next, the CPU 405 detects if the next coordinate value is obtained based on the output value of the A/D converter 404 (S66), and if the output of the A/D converter 404 corresponds to the potential by the input on the touch panel section 401, in other words, if the output is other than the digital value corresponding to 0 volt representing the absence of operation, the CPU 405 delivers a control signal to the x/y control section 403 for switching the respective switches of the switch section 402 (S70), and reiterates the processing from the loading of the coordinate value of y-coordinate (S63). On the other hand, in the step 66, if the output of the A/D converter 404 corresponds to the potential of null input on the touch panel section 401, in other words, if the output is the digital value corresponding to 0 volt representing the absence of operation, it branches to NO for actuating a built-in timer (S67). It also detects if time-out occurs (S68) and if the time in not up, it returns to the step S66 for reiterating the processing. On the other hand, if no input is made during a prescribed period of time on the touch panel section 401 time-up occurs, so it proceeds from the step S68 to the step S69 for supplying the stand-by control section 407 with a switching instruction signal to the stand-by mode. The stand-by control section 407 delivers a control signal through the signal line 409 for changing the respective switches of the switch section 406 from the state of Fig. 1 to the state of Fig. 2. Thus, the stand-by mode as shown in Fig. 2 is provided. Still lower power consumption may be attained by adopting a recently developed processor having a low power consumption mode and a normal operation mode that can be used by selecting one of modes as the CPU 405 of said emhodiment. Namely, when said processor is adopted, it shall be composed to operate in the low power consumption mode if the variation of a predetermined voltage is detected by the logic circuit 410 (stand-by mode), and to operate in the normal operation mode when loading a coordinate value (normal processing mode). Thus, not only the power consumption may be reduced at the touch panel section 401 of the coordinate input section during the stand-by mode but also, the power consumption may be more reduced because the CPU 405 operates in the low power consumption mode. The coordinate input device composed as mentioned above may be applied to a cellular phone having the following character input function. Fig. 6 shows the front view of such a cellular phone. A handset 101 is composed of a rather flat rectangular parallelepipedal case, a ten key (dial key) 103 comprising keys in 4 rows 3 columns from the center to the bottom of the surface thereof and a display section 102 for displaying characters, symbols or other information at the top thereof. Above the display section 102, there is provided a receiver section 104A for listening to the transmitted voice, and below the ten key 103, there is provided a mousepiece section 105A for inputting the voice. Fig. 7 illustrates the inner composition diagram of the forementioned cellular telephone. The cellular telephone comprises a controller 1 for controlling respective parts, a input section 2 for entering information, an antenna 5 for transmitting/receiving a radio wave, a transmission/reception section 3 connected to the antenna 5 for transmitting/receiving signals and a communication circuit 4 for emitting/receiving voice signals between this transmission/reception section 3 and the receiver 104/mouthpiece 105. The receiver 104 and mouthpiece 105 correspond respectively to the receiver section 104A and mouthpiece section 105A of Fig. 6. The controller 1 comprises a communication control section 6 for controlling the communication and a character input/output section 7 for processing character input/output according to the input from the input section 2. The communication control section 6 performs sending control in response to the input from the input section 2, call in control in response to call-accepted signalincoming through the antenna 5 and the transmission/reception section 3, amplitude adjustment in respect of the communication circuit 4 or other controls. Moreover, the communication control section 6 have a function to send through the transmission/reception section data transferred from the character input/output section 7 and to transfer the received data to the character input/output section 7. The input section 2 includes a mode selector switch for switching over between the operation mode as telephone and the operation mode as character input device. This mode selector switch may be a hook switch and, if a hook switch is employed, the operation mode as character input device is selected during on-hook condition. Fig. 8 is a composition diagram of the cellular telephone of Fig. 6 when it is put in the operation mode of character input device. This composition shows the portion comprising the input section 2 and the character input/output section 7 of Fig. 7.The character input device includes a keyboard 11 for entering characters or others, a input control section 12 for collection information of key operation on the keyboard 11 and for delivering to a central control section 13, a central control section 13 for integrally control respective sections of the character input device , a word dictionary 14E which is a dictionary means 310 storing the correspondence between input character or input character string and candidate character or candidate character string as the result of conversion, a dictionary retrieval section 15 for retrieving the corresponding candidate character or candidate character string referring to the word dictionary 14E concerning the input character or character string delivered from the central control section 13, a display device 16 comprising LCD or others for displaying characters or other information, and a display control section 17 for controlling the control for displaying candidate character or candidate character string or others on the display device 16 under the control of the central control section. A plurality of alphabetic letters are distributed to respective numeric keys of the ten key 103 of the keyboardll. Namely, in the usual dial key disposition, three letters, "A", "B" and "C" of the alphabet are allocated to the numeric key "2", three letters, "D", "E" and "F" of the alphabet are allocated to the numeric key "3" and so on up to the key "0". However no letter is allocated to the key "1" or period, comma, apostrophe or other symbols are allocated as mentioned below. To the key "0" are allocated "Q" and "Z". Moreover, "*" key is used as conversion key for directing conversion and retrieval of the next candidate, and "#" key is used as decision key for selecting and confirming the desired word when it is displayed. In the foregoing, the keyboard 11 comprises a plurality of keys to which a plurality of alphabetic letters is allocated, a conversionkey for directing character conversion and a decision key for confirming the result of conversion so as to constitute an input unit 300. The display device 16 constitutes an output unit 330 for at least displaying and outputting candidate character or candidate character string as the result of conversion. The central control section 13 and the dictionary retrieval section 15 constitute a character conversion means 320 for obtaining candidate character or candidate character string through retrieval of the dictionary unit 310 in respect of a character corresponding to a key or of a plurality of characters corresponding to a plurality of keys entered from the input means 300, and for supplying the output means 330 with this candidate character or candidate character string. Fig. 9 is a composition diagram of the said keyboardll. Each key of the ten key 103 is provided with a key matrix 10, one contact of respective switch is constantly supplied with the power of 5V via a pull-up resistor and a line Out 0 - Out 3 along the row and the line Out 0 - Out 3 along the row terminates at the control section 12. On the other hand, the other contact of the respective switch of the key matrix 10 is connected to the line M0 - M2 along the column, and the line M0 - M2 along the column terminates at the input control section. On the other hand. Fig. 10 is a composition diagram of the input control section 15. The input control section 12 comprises a control section for integral control, a timer 21, a memory table 22. a memory (MEM2) 23. a memory (MEM1) 24 and latches 25, 26. The latch 25 is a circuit for latching a drive signal to the line M0 - M2 along the column supplied from the control section 20 and the latch 26 is a circuit for taking and latching the signal of the line Out1 - Out3 along the row. Thetimer 21 is arranged to remove chattering which appears during the key operation and to notify the control section 20 with predetermined time interval (1 mS) for the double reading of the key operation. The drive signal delivered to the latch 25 is set in the memory 23, while the detection signal held by the latch 26 at that time is set in the memory 24. The memory table 22 stores the data for specifying the operated key, the content thereof is shown in Fig. 11. In other words, when the data to be set in the memory 23 is respectively the set value "1", "2" and "3" of MEM2 in Fig. 11, 3 patterns arranged in row making M2 - M0 of 3 rows under MEM2 one set correspond respectively, showing that they are set in the latch 25. Therefore, when one of 3 patterns arranged in row making M2 - M0 of 3 rows under MEM2 one set is set in the latch 25, one of numerals of the set value "1". "2" and "3" of MEM2 in Fig. 11 is set in the memory 23. One of 4 patterns making Out0 - Out3 along right 4 rows of MEM1 in Fig. 11 one set is set in the latch 26 and this value is set in the memory 24. As a result, the numeral of the intersection of one of 4 patterns of MEM1 in Fig.11 and one of set values "1", "2" and "3" of MEM2 represent the numeral of the operated key. For instance, when "1" is set in the memory 23 and "1011" is set in the memory 24, the memory table 22 outputs a code representing "5" key. It shows that "(M2 - M0=)101" is set in the latch 25. The control section 20 reads the key according to the program of the flowchart shown in Fig. 12, so the operation of the control section will be described referring to this flowchart. First, the signal is latched by a latch 25 for outputting "0" to all of lines M0 - M2 along the column (S1), then the appearance of "0" on any of lines Out0 - Out3 along the row based on the signal latched by a latch 26 (S2). When "0" appears, it waits 1 mS referring to a timer 21 (S3) and the signal of the lines Out0 - Out3 in row direction is taken to be sent in a memory 24 (S4). It also comprises the steps of waiting 1 mS referring to the timer 21 (S5), taking the signal of lines Out0 - Out3 in row direction form the latch 26 and detecting if it is equal to the content already set in the memory 24 (S6). Her e. if it is not equal, the operation continues by returning to the step S2 while the result of the first and the second reads is identical, the signal "110(=M2M1M0)" is latched by the latch 25 for outputting "0" only to the line M0 in column direction, "0" is set in the memory 23 (S7) and it is detected where does "0" exist among the signals of lines Out -Out3 in row direction latched by the latch 26 (S8). In other words, when "0" is delivered only to the line M0 in column direction, if one of 4 keys connected to the line M0 In column direction of Fig. 9 is operated, "0" appears on one of signals of lines Out0 - Out3 in row direction. Here, if "0" does not appear on any of signals of lines Out0 - Out3 in row direction, the signal "101" is latched by the latch 25 for outputting "0" only to the line M1 in column direction, "1" is set in the memory 23 (S9) and it is detected where does "0" exist among the signals of lines Out -Out3 in row direction latched by the latch 26 (S10). In other words, when "0" is delivered only to the line M1 in column direction , if one of 4 keys connected to the line M1 in column direction of Fig. 9 is operated, "0" appears on one of signals of lines Out0 - Out3 in row direction. Here again, if "0" does not appear on any of signals of lines Out0 - Out3 in row direction.the signal "011" is latched by the latch 25 for outputting "0" only to the line M2 in column direction, "2" is set in the memory 23 (S11) and it is detected where does "0" exist among the signals of lines Out0 -Out3 in row direction latched by the latch 26 (S12). In other words, when "0" is delivered only to the line M2 in column direction, if one o f 4 keys connected to the line M2 in column direction of Fig. 9 is operated, "0" appears on one of signals of lines Out0 - Out3 in row direction. As the result of the forementioned processing, in any case, if "0" does not appear on any of lines Out0 - Out3 in row direction, the operation continues by returning to the step S1 while if "02 appears on any signal of lines Out0 - Out3 in row direction in any of the said steps S8, S10 and S12, the signal of lines Out0 - Out3 in row direction is taken from the latch 26 and set in the memory 24 (S13). Next, the control section 20 direct the memory table 22 to output, as a result, the memory table 22 is retrieved based on the signal set in memories 23,24 (S14) and the code corresponding to the key output form the memory table 22 is delivered to the central control section 13. Then, the signal is latched by the latch 25 for delivering "0" to all of lines M0 - M2 in column direction (S15), it is detected if all of lines Out0 - Out3 in row direction become (return to) "1" (S16) and, if all "1" is obtained, after waiting 1 mS after the detection referring to the timer 21 (S17), it is detected if all of lines Out0 - Out3 in row direction become (return to) "1" (S18) and, if all "1" is obtained, the operation continues by returning to the step S1. Thus, a code showing which key of the ten key 103 is operated (for instance, a code corresponding to a numeral) is delivered to the central control section 13. Fig. 13 is a detailed composition diagram of the display control section 17 of the character input device. The display control section 17 comprises a character font memory 31 storing character font (character pattern), a character font expansion section 32 for expanding this font stored in the character font memory in a image memory 33 under the control of the central control section 13, a image (bit map) memory 33 for holding by bit map the image data to be displayed on a (LCD) display device 16 and a character position memory 34 for storing the display font data (character code) being displayed with the display position. The said display control section 17 is supplied with display font data, display position data, expansion start instruction signal and position data (address) of the character position memory 34 from the central control section 13. Namely, when the display font data is delivered with the expansion start instruction signal, the character font expansion section 32 accesses the character font memory 31 to take out he display font corresponding to the delivered display font data and stores in the corresponding position of the image memory 33 based on the display position data (coordinates of the image memory 33). As the result, the data position of the image memory 33 corresponding in one-to-one relation to the pixel of the image of LCD display device 16, the pixel data of the display font expanded at the concerned position will be memorized. On the other hand, the character position memory 34 stores the display font data and the display position data at the location of the position data delivered from the central control section 13. As the central control section 13 can read it by unit of a lead signal it can read the data being displayed (display font data) with its display position data and transmit to the other terminal via the communication control section 6, the transmission/reception section 3 and the antenna 5 of Fig. 7. or perform other processing. Fig. 14 is a detailed composition diagram of the dictionary retrieval section 15 of the said character input device. The dictionary retrieval section 15 comprises a control section 40 for integrally controlling the entire dictionary retrieval section 15, a character input buffer 41 for storing character or character string entered from the key, a code pointer 42 used for the dictionary retrieval of the word dictionary 14E and a retrieval result character output buffer 43 for holding codes of candidate character or character string obtained by the dictionary retrieval. Fig. 15 shows the content memorized in the word dictionary 14E Namely, in correspondence to the numeric code by the operation of the ten key 103, dictionary information comprising alphabetic character or character string (word), property information including article, location, time and other information are stored in correspondence at each other. To be more specific, the word dictionary 14E is composed as shown in Fig. 16 to Fig. 18. First, the word dictionary 14E is composed of blocks divides into character number unit as shown in Fig. 16. As shown in Fig. 17, the block corresponding to respective number of characters is composed of a plurality of branches corresponding to numeric string of the concerned number of characters. Here, a plurality of branches corresponding to numeric strings of 5 characters exists in the block of 5 characters and the branch corresponding to the numeric string "25625" among them is shown explicitly while the specific numeral is shown by "*" in other branches. Moreover. Fig. 18 shows the content of the branch corresponding to the numeric string "25625". The branch contains tables corresponding to the following numerals (0) t o (9) if they exist (two tables if only (1) and (8) exist as the following numeral) and a table corresponding to SOS(00) indicating the leading candidate corresponding to the numeric string when there is no following numeral. The table corresponding to the following numerals (0) to (9) contains corresponding following numerals, a pointer NTP of the next table and a pointer NBP of the next branch in set. On the other hand, the table corresponding to SOS (00) contains a code SOS(00) indicating the leading candidate of the case when no following numeral exist ( corresponding to the numeric string "25625" in this case), a character or character string code Strl - Strn (represent n candidates by character code from 1 to n). a code EOS (FF) indicating the end of candidate character or candidate character string code and a code EOB (FF) indicating the end of the branch in set. If a plurality of candidates exist, the co de SOS(00) is registered also between respective ones of the plurality of candidates. If the property information should be memorized, it is set after the character code Strl - Strn of the respective candidate with a symbol indicating the property information. If a plurality of candidate character or candidate character string exist as mentioned above, it is because a plurality of alphabetic letters are allocated to a single key. For instance, when "6" key is operated and then "6" key is operated, as "6" key corresponds to "M", "N" and "0", among string inputs by the combination of any of "M", "N" and "0" corresponding to the first operation of "6" key and any of "M", "N" and "0" corresponding to the next operation of "6" key, as meaningful candidate character strings, words "on", "no" or others exist. While for the numeric string "25625" shown as example in Fig. 18, as meaningful words. "clock", "block" or others exist. In the present invention, it is adopted a method wherein the input is made by sequentially operating the key to which the desired character is allocated among a plurality of keys to which a plurality of characters are allocated respectively. The strings meaningful when they are composed by selecting any one character corresponding to the respective key operation among a plurality of characters generated by the respective key operation through this input are memorized in the word dictionary 14E in string correspondence by the key name (for instance, in correspondence with numeral string if it is numeric key) and the dictionary is retrieved based on the string be the name of the operated key for obtaining a character or character string (word). The control section 40 of the word dictionary 14E shown in Fig . 14 processing the retrieval of the word dictionary 14E according to the program of the flowchart shown in Fig. 19, the operation of the control section 40 will be described according to this flowchart . The control section 40 clears a character input buffer 41 (S21) and waits for the arrival of the code of input character or input character string (code of numeric key) (S22). In this example, the operator wants to enter "clock" as input character as shown in ST1 in Fig. 20. There, the operator operates the corresponding key of the ten key of a cellular telephone. Different from the ten key 103 of Fig. 6. alphabetic letters are indicated directly on the rounded key top of the ten key 103 in Fig. 20. This shows that an appropriate input can be made both by the ten key 103 in the form of Fig. 6 or this ten key 103 of Fig. 20 for this character input device. The numeric key of the ten key 103 is operated "25625" as shown by ST2 in Fig. 20. It is shown that the operator made input desiring the encircled word "clock" among alphabetic letters corresponding to "25625" of ST2. Then, by the operation of the input control section 12 described for Fig. 12, a code corresponding to the operated numeric key is obtained and a code string corresponding to the said "25625" is stored in the character input buffer 41. Next, the operator presses "*" key, that is conversion/next candidate key for conversion as shown by ST3 in Fig. 20. The operation of this "*" is also converted into a code by the operation of the input control section 12 described for Fig. 12 and then delivered to the central section 13. On reception, the central control section 13 transmits a retrieval start signal to the central control section 40 of Fig. 14 There, as shown in Fig. 19, the control section 40 monitoring the retrieval start (S23) resets a code pointer 42 (S24) and put a data selector signal in set state (S25). Next, the control section 40 takes out codes stored in the character input buffer 41 from the beginning and start the retrieval from the block of single character of the word dictionary 14E. The retrieval procedure is identical for any number, so the description will begin with the retrieval in the block of 3 characters. Fig. 21 is a diagram for illustrating the processing from the retrieval in the block of 3 characters. It arrives at the table of the address "3F0F" of the block of 3 characters in response to the numeric string "256". The following number in this table is "1" and different from the fourth number "2" of the numeric string "25625" stored in the character input buffer 41, so the next table will be retrieved based on NTP. Here exist only a candidate with the numeral "1" following the numeric string "526" and a candidate with "2". Usually, tables of following numerals as much as they exist such as table with the following numeral "1", then table with the following numeral "2", then table with the following numeral "3" and so on before arriving at the table of the required following numeral. When the following numeral agrees, it arrives at the first table of the branch "2562" of 4 characters based on NBP of this table. In this table, as the following numeral is "5", it agrees with the fifth numeral "5" of the numeric string "25625" stored in the character input buffer 41. When the following numeral agrees, it arrives at the next branch "25625" based on NBP of this table. Here, originally, as there is no following numeral stored in the character input buffer 41, it retrieves a table wherein "00" is set in the area of following numeral. In this example of Fig. 21, it is supposed there is no candidate having a numeral following the numeric string "25625" even in the word dictionary 14E or no table, it arrives from the table of the branch "2562" directly to the table of the address "98AC" where "00(=SOS)" is set in the area of following numeral. In the example of Fig. 21, as "clock" is set by code "63, 6C, 6F, 63, 6B" in the first candidate character string, the code "63, 6C, 6F, 63, 6B" of the concerned "clock" is read in response to the output value "0" of the code pointer 42. The forementioned processing corresponds with the processing from "Retrieval" (S25) to the loop (S26, S27, S28) in Fig. 19. The increment of the code pointer 42 in the step 27 corresponds to the sequential table retrieval in Fig. 21 and, at the same time, to the read-out by specifying respective candidate character in the target table. Therefore, in practice, the retrieval of candidate character made in Fig. 21 is equivalent to the retrieval of the word dictionary 14E s hown in Fig. 15. In this example "clock" is obtained, however, if a candidate character corresponding to the entered numeric string does not stored in the word dictionary 14E, the value is increased by supplying the code pointer 42 with NEXT signal (S27), the loop from S28 to S26 is reiterated and eventually. If candidate character or candidate character string can not be retrieved, it branches to YES at S28. In other words, END signal is returned from the code pointer 42. There, the control section 40 transmits "No candidate" as retrieval result information to the central control section 13. Receiving this "No candidate", the central control section 13 supplies the display control section 17 with character font "No candidate" for displaying that no candidate exist by means of LCD display device 16 (S29). The code of "clock" obtained as mentioned above is transmitted to the retrieval result character output buffer 43 (S30). Base on the retrieval result information, the central control section 13 is notified with the result output, the code of "clock" is taken into the central control section 13 from the retrieval result character output buffer 43, transmitted to the display control section 17 and then delivered to the (LCD) display device 16 for visualization as described for Fig. 13. Namely "clock" is displayed on the (LCD) display device 16. The control section 40 of the word dictionary 14E monitors the operation of the decision key or the next candidate key (S31, S32). The operation of the decision key or the next candidate key is transmitted from the input control section 12 to the central control section 13 as in the operation of the forementioned conversion key. In the example of Fig. 20, as "clock" is the desired character the decision key is pressed as shown in ST4. Receiving the code of the decision key, the central control section 13 shifts the retrieval signal to inactive. Receiving this, the control section 40 of the dictionary retrieval section 15 branches to YES from the step 31 for confirming the said candidate character. When first "block" and then "clock" are stored in the word dictionary 14E in correspondence with "25625", first "block" is displayed as shown in parentheses at ST5 in Fig. 20, the next candidate key is operated in response to this, the value of the code pointer 42 is increased by receiving NEXT signal (S27), the code of the next candidate "clock" is obtained for proceeding from S26 to S30. In this case also, as "clock" is the intended word, the decision key is pressed as shown in ST4. The further processing is as shown above. Fig. 22 is a partial composition diagram concerning the character input function of the coordinate input device according to an embodiment of the invention applied to a cellular telephone described above. In this composition portion for character input, a touch panel 50 (corresponding to the touch panel section 401 of Fig. 1) is disposed by attaching to the screen of a display device 16 and an input control section 12-A detects the operation input coordinates value from this touch panel 50. Namely , a coordinate input section composed of a touch panel section 101 as described for Fig. 3 and Fig. 4 is attached to the screen of a display section 102 corresponding to the display device 16. As described for Fig. 1 and Fig. 2, in response to the coordinate input on this coordinate input section, the input control section 12-A detects disposed in the case of a cellular telephone the position (coordinates) of the operation. In other words, the input control section 12-A comprises the composition other than the touch panel of the coordinate input device according to an embodiment of the present invention and constitutes a position detection means 55 for detecting the input operation position on the touch panel 50 of Fig. 22. Fig. 23 is a flowchart for illustrating the operation of the dictionary retrieval section 40 of the dictionary retrieval section 15 of a character input device composed as shown in said Fig. 22. In this embodiment, the processing corresponding to the steps S30 - S32, S27 of Fig. 14 performed by the character input device of the composition as mentioned above will be executed as shown in Fig. 23. That is to say,a predetermined number of candidates, as existing, from the word dictionary 14E and supplied to a character output (for LCD display) buffer 43 with "next candidate" character (or "scroll") (S30-A). In response to this, if a numeric string "227" is input and the conversion key is operated, the display control section 17 displays "bar", "cap", "car", "next candidate" at the position of the transparent electrode 52 of the display screen of the display section 102 as shown at the bottom the Fig. 25.The control section detects the operation position on the touch panel 50 (S37), detects the candidate character displayed in correspondence with the coordinates of the operation position (S38) and confirms this candidate character (S40). Now, the detail of the processing concerning the detection of the operation position on the touch panel 50 and the detection of the candidate character displayed in correspondence with the coordinates of the operation position assumed by the control section 40 will be described. The control section 40 is supplied with coordinate values concerning the input operation on the touch panel from the input control section 12 -A including essential parts of the coordinate input device according to an embodiment of the present invention. The control section 40 includes, as shown in Fig. 24, a table for confronting said coordinates (x, y) and the candidate character or string, and the region number of the "next candidate" string, so, for instance, when coordinates (xi, yi) are obtained, the region number "2" will be detected. As shown in Fig. 25, from the left, candidate number "1", "2", "3" and "4" are allocated to the code of candidate character or string and to the code of "next candidate" in correspondence with the region number. The control section 40 holds also information about the correspondence of candidate numbers with the code of candidates (including code of "next candidate") delivered to the display control section 17 (that is, candidates being displayed). Therefore. when the display control section 17 is supplied with candidates as shown in Fig. 25 and the coordinate values (for instance, xi, yi) corresponding to the region number "2" is obtained, it may be detected that the candidate having the candidate number "2" is selected, namely, "cap" is selected. On the other hand. the operation of the next key (or the region of "next candidate") is detected at the step S38 o said Fig. 23, the pointer for display is changes (S39), the code pointed 42 is incremented by said predetermined number of candidate (by 3 in the example of said Fig. 25) (S27-A) before proceeding to the retrieval of other candidates. In other words, when the pointer for displaying candidates for candidate string of the corresponding table of the word dictionary 14E and the pointer for retrieving candidate characters form within the table of the word dictionary 14E are common, by incrementing them by 3, next 3 candidates are taken out, if they exist, and displayed. Thus, a cellular telephone adopting the coordinate input device according to an embodiment of the present invention may display simultaneously a plurality of candidates if they exist and select by the touch panel 50 so as to allow advantageously to confirm the candidate character surely and rapidly. It goes without saying that it can effectively reduce the power consumption of the cellular telephone.

Claims: A coordinate input device comprising: a coordinate input section (401) wherein a first conductive sheet (151) for x-coordinate detection provided with electrodes (x1, x2) on a pair of end edges and a second conductive sheet (152) for y-coordinate detection provided with electrodes (y1, y2) on a pair of end edges are superposed though a spacer (153) so that respective electrodes intersect orthogonally, selection means (402) for selecting a signal from either of said first and second conductive sheets (151, 152), a central control section (405) for loading coordinate values through said selection means, a stand-by control section (407) for switching, responsive to said central control section (405), between applying a predetermined voltage between said both electrodes (x1, x2) of said first conductive sheet (151) or between said both electrodes (y1, y2) of said second conductive sheet (152) and applying a predetermined voltage between one of said electrodes of said first conductive sheet (151) and one of said electrodes of said second conductive sheet (152), an A/D converter (404) for converting a signal from either of said first and second conductive sheets (151, 152) into a digital coordinate value, and a logic circuit (410) for transmitting, responsive to said stand-by control section (407), variation in a predetermined voltage to said central control section (405) when the predetermined voltage is applied between one of said electrodes of said first conductive sheet (151) and one of said electrodes of said second conductive sheet (152), wherein said central control section (405) shifts to a mode for loading the coordinate values while said logic circuit (410) monitors variation in a predetermined potential, where the logic circuit (410) generates an interrupt signal separate from an output of the A/D converter (404) responsive to detecting the variation of the predetermined voltage, characterized in that said central control section (405) directs said stand-by control section (407) to apply a predetermined voltage between one of said electrodes of said first conductive sheet (151) and one of said electrodes of said second conductive sheet (152) if no coordinate value is inputted over a predetermined period of time. A coordinate input device according to claim 1, characterized in that said central control section (405) directs said stand-by control section (407) to apply a predetermined voltage between said pair of said electrodes of said first conductive sheet (151) or said pair of said electrodes of said second conductive sheet (152), while the logic circuit (410) monitors the variation in the predetermined voltage during the detection of the predetermined voltage. A coordinate input device according to claim 1, characterized in that said central control section (405) operates in either one of low power consumption mode and normal operation mode, and operates in the low power consumption mode, while the logic circuit (410) monitors the variation of the predetermined voltage. A coordinate input device according to claim 1, characterized in that said central control section (405) operates in either one of low power consumption mode and normal operation mode, and operates in the normal operation mode, during the loading of coordinate values. A coordinate input device according to claim 1, characterized in that an A/D converter (404) is arranged between said central control section (405) and said selection means (402), and said central control section (405) is provided with a correspondence table of said A/D converter (404) output values and one of x-coordinate and y-coordinate values, thereby obtaining x and y coordinate values from said A/D converter (404) output values responsive to the table. A coordinate input device of claim 1, characterized in that said first conductive sheet (151), said second conductive sheet (152) and said spacer (153) are respectively transparent. A coordinate input device of claim 6, characterized in that said coordinate input section (401) is arranged on a screen of a display device (102). A coordinate input device of claim 6, characterized in that the coordinate input section (401) is disposed on a screen (102) of a cellular telephone (101) display, and the mode control means (405) is enclosed in a body of the cellular phone (101). A coordinate input device of claim 1, characterized in that said spacer (153) insulates between said first and second conductive sheets (151, 152) if the second conductive sheet (152) is deformed toward the first conductive sheet (151). A coordinate input device of claim 9, characterized in that said spacer (153) is composed of transparent aeolotropic conductive rubber sheet, current flows through the sheet to only a direction. A coordinate input device of claim 9, characterized in that said spacer (153) is composed of a lattice material. A coordinate input device of claim 9, characterized in that said spacer (153) is composed of a sheet having a plurality of holes formed thereon.

Inventors: INOUE NOBUHIRO, IWAKI JITSU, KISAICHI KAZUHIRO, NANNICHI TOSHIHIKO, NOSE TOSHIRO, INOUE, NOBUHIRO, IWAKI, JITSU, KISAICHI, KAZUHIRO, NANNICHI, TOSHIHIKO, NOSE, TOSHIRO
Applicants: TOSHIBA KK, KABUSHIKI KAISHA TOSHIBA
Application year: 1996
Main classification: G06K11
IPC codes: G06F3