Coordinate input device

[0001] [Technical field to which the invention belongs] The present invention relates to a coordinate input device for inputting a locus when characters or figures are handwritten on a paper with a dedicated pen as character data or graphic data to a computer. The present invention relates to an ultrasonic coordinate input device having a small blind spot area and good operability and portability.

[0002] [Conventional Technology] With the recent spread of personal computers, it is becoming more common to input electronic documents using a keyboard rather than handwriting characters on paper using a pencil or the like, but it is easy. When writing notes, it is easier to actually handwrite characters on paper than to type on the keyboard.

[0003] For this reason, it is still common to bring a memo pad or the like and handwrite it into the memo pad or the like using a pencil or the like when holding a meeting or the like, but the created memo is distributed to others. Considering the management and management, it is desirable that such memos be digitized. In particular, if handwritten characters are read by an image scanner or the like, the processing required for digitization is complicated, and using a touch panel or tablet is inconvenient to carry, so it is desirable to easily input the handwritten characters as electronic data. It is rare.

[0004] From these facts, conventionally, a pair of ultrasonic receivers are arranged on a paper, and the ultrasonic waves transmitted from the pen are received by these ultrasonic receivers, and the propagation time of the ultrasonic waves is calculated as a triangle. A coordinate input device for inputting coordinates by surveying is known. For example, in Japanese Patent Application Laid-Open No. 8-36462 and Japanese Patent Application Laid-Open No. 2000-298547, two receivers constituting a receiver are arranged on a desk or a base, and ultrasonic waves propagate to these receivers. A technique is disclosed in which the distance between the pen and the receiver is continuously measured from the propagation time, and the pen coordinates with respect to the desk are obtained by using the triangulation method. An infrared receiver is provided on the desk in order to synchronize the time when ultrasonic waves are generated from the pen, and the infrared receiver from the pen receives infrared rays.

[0005] [Problems to be Solved by the Invention] However, when the conventional technique that employs such triangulation is used, an area that becomes a blind spot is generated in a part of the paper, and it becomes impossible to input coordinates, even if Even if input is possible, there is a problem that the resolution deteriorates as a result. Further, if an attempt is made to avoid such a blind spot, there arises a problem that the size of the device is increased and the cost is increased.

[0006] FIG. 17 is a diagram showing an example of the configuration of a conventional coordinate input device. As shown in Fig. (A), in triangulation, the wider the distance W between the two receivers that make up the receiver, the better the coordinate resolution, which is the degree of discrimination. Therefore, two ultrasonic receivers 130 and one There is known a coordinate input device in which the receiver 132 having the infrared receiver 131 of the above is elongated. The long receiver 132 is usually arranged at a position substantially parallel to the upper side of the paper.

[0007] However, since the directivity of the ultrasonic receiver or the infrared receiver is generally about ± 45 to 60 degrees, there is a problem that an area serving as a blind spot is generated on the left and right sides of the upper end portion of the paper. In other words, for example, when the position of the pen (writing position) is at point A in the figure, the coordinates cannot be input due to the directivity limitation of ultrasonic waves and infrared rays, or even if they can be input, the resolution is significantly deteriorated. The problem of closing up arises.

[0008] In order to eliminate the blind spot caused by the directivity of the ultrasonic waves and infrared rays, as shown in FIG. 17 (b), it is necessary to fix the receiver 132 apart from the paper by using a jig or the like. However, in this case, the occupied area of the device becomes wide. It is also conceivable to arrange a plurality of receivers 130 or attach a reflector to expand the directivity, but in this case, the device becomes large and costs increase, and a large space is still required. turn into.

[0009] Therefore, as shown in FIG. 17 (c), it is conceivable to arrange the receiver 132 at the corner of the paper, but also in this case, since the receiver 132 is long, it is also an apparatus. There is a problem in terms of operability that the area occupied by the paper becomes large and it is difficult to use. As shown in FIG. 17 (d), if the receiver 132 is arranged inside the corner of the paper to reduce the occupied area of the device, the points B and C become blind spots. The problem arises.

[0010] From these facts, it is an extremely important issue how to realize an ultrasonic-based coordinate input device having few blind spots and good operability and portability.

[0011] The present invention has been made to solve the above-mentioned problems of the prior art, and provides an ultrasonic coordinate input device having a small blind spot area and good operability and portability. The purpose is to provide.

[Means for Solving the Problems] In order to solve the above-mentioned problems and achieve the object, the coordinate input device according to claim 1 has a pen that emits ultrasonic waves and a pen that emits ultrasonic waves. A coordinate input device that has a receiver that receives ultrasonic waves with a plurality of ultrasonic receivers and inputs the coordinate position of the pen based on the propagation time of the ultrasonic waves received by each ultrasonic receiver of the receiver. The receiver is a sandwiching means for sandwiching a plurality of ultrasonic receivers that receive ultrasonic waves transmitted from the pen and a corner portion of a predetermined sheet.<u style="single">And an edge portion formed of approximately 90 degrees to which the corner portion of the paper sandwiched by the sandwiching means is abutted, and the plurality of ultrasonic receivers have the corner portion of the paper on the edge portion. The angle between the upper side of the paper and the straight line connecting the plurality of ultrasonic receivers when they are in contact with each other is in the range of 30 to 60 degrees.</u>It is characterized by that.

[0013] According to the invention of claim 1, the receiver<u style="single">When the corners of the paper come into contact with the edges of the multiple ultrasonic receivers provided in, the angle between the top edge of the paper and the straight line connecting the multiple ultrasonic receivers is 30 to 60 degrees. Since it is arranged so as to be within the range of, by inserting the paper along the edge part, the arrangement angle of the ultrasonic receiver with respect to the paper is automatically arranged at the tilt position of 45 degrees which is the maximum directivity. This makes it possible to cover the entire area of the paper, so that the configuration of the coordinate input device can be miniaturized without creating a blind spot area, and it is easy to operate and portable. It can be used for use. In addition, it is possible to prevent the apparent receiver spacing from becoming narrower from the pen, avoiding the problem of deterioration in resolution.</u>can do.

[0014] Further, in the invention of claim 1, the coordinate input device according to the invention of claim 2 is a flat plate-shaped board (FIGS. 12 and 13) on which the paper for writing is placed by the holding means. It is characterized by being fixed to (corresponding to board 802).

[0015] According to the invention of claim 2, since the receiver is arranged and fixed in advance at the corner of the board by the holding means, it is possible to cover the entire range of the paper surface if it has a directivity of ± 45. Therefore, no blind spot is generated, and the board on which the paper is placed functions as an underlay, so that it can be used as a portable device with good operability and portability during writing.

[0016] Further, in the invention according to claim 1 or 2, the coordinate input device according to claim 3 has an infrared transmitter that emits an infrared pulse, and the receiver is the infrared transmitter. It is further provided with an infrared receiver (corresponding to the infrared receiver 305 in FIG. 3) that receives an infrared pulse transmitted from the above as a synchronization signal.

[0017] According to the third aspect of the present invention, it is possible to transmit an infrared pulse synchronization signal to the receiver without connecting the pens by wire.

[Embodiments of the Invention] Hereinafter, preferred embodiments of the coordinate input device according to the present invention will be described in detail with reference to the accompanying drawings.

(Embodiment 1) First, the configuration of the coordinate input device according to the first embodiment will be described. FIG. 1 is a system configuration diagram with a personal computer which is an application example of a coordinate input device, FIG. 2 is an explanatory diagram showing an arrangement example of a receiver, and FIG. 3 is a configuration diagram of a receiver (top view, front view, side view). Figure) is shown respectively.

That is, as shown in FIG. 1, the coordinate input device 100 of the present invention includes a receiver 101 having two ultrasonic receivers 304 (FIG. 3) and an infrared receiver 305 (FIG. 3) and a writing means. It is composed of a dedicated pen 102 as a device, and is used by connecting the connection cable 103 of the receiver 101 to the USB port of a personal computer or the like. In the case of the coordinate input device 100 as in the conventional case, when characters and figures are handwritten on the paper by the pen 102, the locus is input to the computer 104 as data and can be used as character data and figure data. ..

Here, FIGS. 2 (a) and 2 (b) are explanatory views showing an arrangement example of the receiver 101, and as shown in FIGS. 2 (a) and 2 (b), the receiver 101 is compact in the present embodiment. A major feature is that it can be placed in the "corner of the paper" where the blind spot of the receiver is eliminated by configuring it (miniaturization). That is, as shown in FIGS. 2A and 2B, in the first embodiment, the receiver 101 is arranged at either the left or right corner of the paper surface, for example, a right-handed person. In the case of, it is preferable to place the receiver 101 in the upper right (Fig. 2 (a)). This is to prevent the ultrasonic waves and infrared rays from being transmitted from the pen with the left hand when the paper is pressed with the left hand. On the contrary, in the case of a left-handed person, the receiver 101 is placed on the left side (Fig. 2 (b)) and used. Hereinafter, the feature portion of the first embodiment will be mainly described.

[0026] FIG. 3 is a configuration diagram of a receiver, and shows (a) an upper view, (b) a front view, and (c) a side view, respectively. In addition, FIGS. 4 (a) and 4 (b) are diagrams illustrating a procedure for fixing the paper by the receiver. Hereinafter, the configuration of the receiver will be described with reference to FIGS. 3 and 4. That is, as shown in FIG. 3, the receiver 101 is configured in a so-called clip type having a thick-walled upper half 302 and a thin-walled lower half 303, and the upper half 302 are positioned at predetermined positions of each other. Two separate ultrasonic receivers 304 and one infrared receiver 305 located approximately in the center of these ultrasonic receivers 304 are mounted. Of these, the ultrasonic receiver 304 is made of a cylindrical piezoelectric film made of polyvinylidene fluoride.

[0027] Further, since the base end side (right side in the figure) of the upper half 302 and the lower half 303 is pivotally supported by the pivot 306, the upper half 302 and the lower half 303 refer to the pivot 306. It can be opened and closed (Fig. 4 (a)) as a base point, and can hold and fix a predetermined position on the paper (Fig. 4 (b)). Then, the receiver 101 configured in this way is arranged and fixed to the corners of the paper.

[0028] Here, when the receiver 101 is arranged substantially parallel to the paper as described in the conventional problem, a blind spot is generated in the ultrasonic receiver 304 and the infrared receiver 305, or an apparent interval is formed. Has been found to be narrower. Therefore, as shown in FIG. 5, in the first embodiment, the fixed position of the receiver 101 is the angle formed by the straight line connecting the two receivers 304 and the upper side of the paper from the viewpoint of the apparent spacing of the receiver 304. It is characterized by arranging and fixing it at an angle so that the temperature is 30 to 60 degrees.

That is, as shown in detail in FIG. 7A, in the case of the receiver 304 in FIG. 5, the method of arranging the two receivers 304 is described by the straight line connecting the two receivers 304 and the upper side of the paper. The angle between the two is limited to 30 to 60 degrees. In this case, the orientation of the receiver 304 itself is not particularly considered.

Then, going back further, as shown in FIG. 6, the orientation of the two receivers 304 is 30 to 60 with respect to the upper end of the paper, which is the maximum sensitivity direction (direction of the arrow) of the receiver 304. It can be said that it is appropriate from the viewpoint of directivity to fix the receiver 304 so that the direction (direction) of the degree is set.

That is, as shown in detail in FIG. 7 (b), in the case of the receiver 304 in FIG. 6, the orientations (directions) of the two receivers 304 are directed with respect to the upper end portion of the paper which is the maximum sensitivity direction. The orientation is limited to 30 to 60 degrees. In this case, the arrangement of the two receivers 304 itself is not particularly considered.

[0032] As shown in FIG. 8, more preferably, the angle between the straight line connecting the two receivers 304 and the upper side of the paper is 45 degrees, and the maximum sensitivity direction of the receivers 304 is received by two. Fix the angle between the straight line connecting the vessels 304 and 90 degrees, that is, the top edge of the paper at 45 degrees. In order to do so, as shown in FIG. 3, an edge portion 307 set at an angle (inclined portion) of approximately 90 degrees is formed on the surface of the lower half portion 303 constituting the receiver 101. As a result, when fixing the corners of the paper with the receiver 101, the paper is inserted along the edge 307 to automatically set the arrangement angle of the receiver 101 with respect to the paper at 45 degrees, which is the maximum directivity. Can be placed at the tilted position of.

[0033] In this example, the formation position of the edge portion 307 is set to the lower half portion 303 side, but even if the edge portion 307 is formed on the upper half portion 302 side, the arrangement angle of the receiver 101 is similarly maximized. It is possible to obtain the effect that it can be arranged at an inclined position of 45 degrees, which is the directivity of.

[0034] As described above, the feature of the present invention is the arrangement of the receiver 101 in order to eliminate the blind spots of the two ultrasonic receivers 304 provided in the receiver 101 and not to narrow the apparent distance between them. It is configured so that the position is the corner of the paper. Then, in order to arrange the receiver 101 at the corner of the paper in this way, it is necessary to reduce the distance W between the two receivers and to make the size of the receiver 101 itself compact and compact. This is because, as described above, if the receiver interval W is large, good resolution can be obtained, but on the other hand, a blind spot is generated and the device becomes large.

[0035] That is, the variation in the distance measurement by the ultrasonic wave is caused by the temperature fluctuation in the air propagated by the ultrasonic wave and the sensor amplifier noise of the receiver, both of which are the receiver 304 and the pen point ( It increases in proportion to the distance L, which is the distance from the writing position by pen 102). Furthermore, it has been found that the coordinate variation e in triangulation is proportional to the distance L and inversely proportional to the receiver distance W between the two receivers 304. Therefore, the present inventor conducted an experiment as shown in FIG. 9 in order to maintain the required resolution and obtain the receiver interval W of the selected value as small as possible (relationship diagram between distance and error).

[0036] Hereinafter, the experimental results of FIG. 9 and the principle diagram for explaining the arrangement of the receiver of FIG. 6 will be described. In this experiment, the receiver spacing W was selected to be 25 mm, and the relationship between the distance and the coordinate variation was obtained by experiment. Specifically, the measurement distance variation when the ultrasonic receiver 304 and the pen 102 were gradually separated. An experiment was conducted to see how much Here, the horizontal axis in the figure is the actual distance value (mm), the vertical axis is the error (mm), the black dot is the measured value of the distance obtained by the ultrasonic receiver, and the graph is the calculation calculated by the calculation formula. The transition by value is shown respectively. From this measurement result, the coordinate variation e in triangulation is e = 0.0002L.²It can be calculated as an approximate value from the formula of / W.

Then, if the size of the paper to be used (the length of the diagonal line of the paper) and the required resolution are determined by back calculation from the above-mentioned calculation formula, the required minimum receiver interval W can be obtained. .. That is, when the receiver 101 is fixed to the corner of the paper, the diagonal length is the farthest distance, and this distance is the farthest distance between the receiver 304 and the pen point. In addition, since a resolution of ± 0.1 to 1 mm is required for actual normal writing, if the diagonal length P (replace the distance L, which is the pen point position, with P), the receiver spacing W is W = 0.0002P²~ 0.002P²It can be calculated from the formula of.

[0038] Then, based on this calculation formula, in the invention of the first embodiment, when the diagonal length on the paper is P, the set value of the arrangement interval W between the two receivers 304 is 0.0002. P²Greater than 0.002P²It is supposed to be smaller than. When the receiver 101 is configured by arranging the receiver 304 based on the receiver interval W set in this way, the receiver 101 can be miniaturized and the maximum directivity is obtained. It is possible to arrange the receiver 101 at the corners of the paper that can be used.

[0039] As described above, the receiver 101 according to the first embodiment has an upper half 302 having a pair of ultrasonic receivers 304 and an infrared receiver 305, and a base end portion of the upper half. It is configured as a fixing member that can hold and fix the corners of the paper consisting of the lower half 303 that is pivotally supported, and the fixing position for the paper by the receiver 101 is the straight line connecting the pair of ultrasonic receivers 304. Since the angle between the top edge of the paper and the paper is set to a position in the range of 30 to 60 degrees, there is no blind spot in the receiver 304, and the apparent spacing of the receiver 304 is not narrowed. As a result, the configuration of the device can be miniaturized, and it can be used as a portable device with good operability and portability.

Next, the configuration of the dedicated pen applied to the present invention will be described with reference to FIG. That is, as shown in FIG. 10, a ballpoint pen core 702 for writing is attached to the tip of the pen 102, and the contact between the ballpoint pen core 702 and the writing surface of the paper is detected inside the pen 102. A contact detection switch 703 is provided. In addition, a cylindrical ultrasonic transmitter 704 and an infrared transmitter 705 are provided on the tip side of the pen 102, of which the ultrasonic transmitter 704 is composed of a piezoelectric film (PVDF) made of polyvinylidene fluoride. Has been done. This piezoelectric film has a function of vibrating and generating ultrasonic waves when a voltage is applied.

[0041] Here, the shape of the ultrasonic transmitter 704 is a cylindrical shape capable of setting the directivity of the ultrasonic wave to 360 degrees. Therefore, even if the pen 102 rotates during writing, the transmitted ultrasonic pulse can be accurately reached to the receiver 304. In addition, three infrared transmitters 705 with a directivity of 120 degrees are evenly arranged, and even if the pen 102 rotates during writing, the transmitted infrared pulse can be accurately reached to the receiver 304. ..

[0042] Further, 708 is a drive circuit unit, and the drive circuit unit 708 is driven by a AAA battery 709. Specifically, when writing by hand, the contact detection switch 703 is turned on only when the tip of the pen 102 touches the writing surface of the paper, and ultrasonic waves and infrared rays are transmitted. In this way, power saving is achieved by preventing the transmission of ultrasonic waves and infrared rays at times other than when writing with the pen 102.

FIG. 11 is a block diagram showing a circuit configuration of a drive circuit unit 708 applied to the dedicated pen 102 described above. That is, as shown in FIG. 11, the drive circuit unit 708 includes a timer 710, an infrared drive circuit 711, and an ultrasonic drive circuit 712, and the core 702 of the pen 102 and the writing surface of the paper come into contact with each other, and this contact is detected. When detected by the switch 703, the infrared drive circuit 711 and the ultrasonic drive circuit 712 are operated by the timer 710 to generate an infrared pulse from the infrared transmitter 705 and an ultrasonic pulse from the ultrasonic transmitter 704 for a fixed period (50 Hz to 100 Hz). Occurs. The cycle here is set to be a constant cycle of about 50 Hz so that the movement of the pen 102 by a human hand can be stably detected.

(Embodiment 2) Next, the configuration of the coordinate input device 801 according to the second embodiment will be described with reference to FIG. Of these, FIG. 12 (a) shows a plan view, and FIG. 12 (b) shows a side view. Here, in the second embodiment, the difference from the first embodiment described above is that a flat plate 802 (corresponding to the lower half 303) is placed below the upper half 302 constituting the receiver 803. The feature is that the paper is placed on the upper part of this board 802.

That is, the upper half 302 and the base end side (right side in the figure) of the board 802 are pivotally supported by the pivot 306, and the upper half 302 can be opened and closed with respect to the board 802 with the pivot 306 as the base point. Since it is shown in (Fig. 12 (b)), the corners of the paper can be sandwiched and fixed to the board 802.

[0046] Further, the plate thickness of the board 802 is selected to be a thin wall thickness, and is selected to have substantially the same size as the paper size (for example, A4 size).

[0047] Further, the position where the receiver 803 is fixed to the board 802 is selected so that the angle with the upper side of the board 802 is in the range of 30 to 60 degrees as well as the corner portion of the board 802. Specifically, the orientation is 45 degrees, which maximizes the directivity toward the paper.

[0048] Further, as described above, since the board 802 used in the second embodiment is selected to have a thin thickness, it functions as an underlay for paper and is not unsuitable for carrying like a tablet. As a result, it can be used as a coordinate input device that is convenient to carry. The size of this board 802 is not limited to the frequently used A4 size, etc., and when the dimensions are selected for a smaller size such as the B5 size, it is used as a coordinate input device 801 that is more suitable for carrying. can do.

As described above, the coordinate input device 801 according to the second embodiment is provided with a flat plate-shaped board 802 corresponding to the lower half 303 below the upper half 302 constituting the receiver 803. The paper was placed on the top of the board 802, and the corners of this paper were selected and fixed so that the angle with the top side of the board 801 was in the range of 30 to 60 degrees. Since the blind spot of 304 does not occur, the apparent interval of the receiver 304 is not narrowed, and the board 802 functions as an underlay, the operability and portability at the time of writing by the pen 102 are good and it can be used as a portable device. it can.

[0050] Further, FIG. 13 shows a coordinate input device 805 in which the receiver 803 and the clip 809 which is the holding means are separated, the clip 809 is provided on the upper part of the board 802, and the paper is sandwiched by the clip 809. It is a thing. Also in this case, the fixed position of the upper half 302 with respect to the board 802 is selected so that the angle with the upper side of the board 802 is in the range of 30 to 60 degrees as well as the corner of the board 802. Specifically, the orientation of the receiver 304 with respect to the paper is 45 degrees, which is the maximum.

[0051] In this case, since the paper can be fixed by the clip 809, it is not necessary to provide a mechanism for sandwiching the paper, such as providing a pivot 306 on the upper half 302 as described above.

[0052] FIG. 14 is an example of an internal block diagram which is an electric circuit of a receiver applicable to the first and second embodiments, and FIG. 15 is a waveform of an ultrasonic pulse received by an ultrasonic receiver (FIG. 15). Timing charts) are shown respectively.

That is, as shown in FIG. 14, the internal circuit is an input amplifier 111a, 111b that amplifies the ultrasonic pulse received by the ultrasonic receiver, a comparator 112a, 112b for comparison, a zero cross comparator 113a, 113b, FF114a, It is composed of 114b (flip flop), timers 115a, 115b, and microcontroller 116. Then, the ultrasonic propagation times T1 and T2 can be detected by the electric configuration configured in this way.

First, the timer 115a (115b) starts (Start signal) when the infrared receiver 305 (FIG. 3) receives the infrared pulse transmitted from the infrared transmitter 705 (FIG. 10). The ultrasonic pulses received by the two ultrasonic receivers 304 are then amplified to an appropriate magnitude by the input amplifier 111a, respectively (see FIG. 15). Hereinafter, among the ultrasonic pulses after amplification by the input amplifier 111a, the threshold value rt1 as a threshold is taken out by the comparator 112a, and when the ultrasonic pulse is larger than this threshold value rt1, FF114a (flip-flop) is turned ON. Further, the zero cross comparator 113a detects the zero cross (point Z), and the timer 115a is stopped (Stop signal) by the logical product (and) of both of them. At this time, the next zero cross position that exceeds the threshold value rt1 is detected. The time when this zero cross position is detected is the arrival time of the ultrasonic pulse to the receiver.

Therefore, based on the infrared synchronization signal from the infrared transmitter 705, the ultrasonic propagation time T1 until the arrival of the ultrasonic pulse is detected by a timer. Hereinafter, the propagation time T2 is detected for the other ultrasonic receiver 304 by the same sequence, and the propagation times T1 and T2 detected in this way are input to the microcomputer 116. As will be described later, the distance from the pen point, which is the writing position, to the receiver 304 can be calculated based on the propagation times T1 and T2 detected in this way.

FIG. 16 is a flowchart showing processing inside the microcomputer and the personal computer. With reference to this flowchart, a method of calculating the coordinates on the personal computer from the detected ultrasonic wave propagation times T1 and T2 will be described. That is, as shown in FIG. 12, first, as the processing of the microprocessor 116, the processing of reading the propagation times T1 and T2 from the timers 115a and 115b, respectively, is performed (step: S120). Transfer these read propagation times T1 and T2 to the personal computer via the USB port (step: S121).

The following is a process inside the personal computer. Inside the personal computer, a process of reading the propagation times T1 and T2 from the microcontroller 116 is performed (step: S122), and then a pen is performed from these propagation times T1 and T2. Perform distance calculation to calculate distance L1 and distance L2, which are the distances between the point and the two receivers 304 (step: S123). That is, assuming that the speed of sound is V and the distance between the receiver and the receiver is W, the distance L1 and the distance L2 can be calculated by the formula of L1 = V × T1 L2 = V × T2.

Next, a coordinate calculation process for calculating the coordinate position on the personal computer is performed based on the distance L1 and the distance L2 calculated by the above calculation formula (step: S123) (step: S124). That is, if the position of one of the two receivers 304 is taken as the origin and the position of the other receiver 304 is taken as the coordinate system (W, 0), the coordinates (x) of the predetermined pen are taken. , y) is x²+ y²= L1²(xW)²+ y²= L2²Therefore, when x and y are solved by these formulas, the coordinates are [Equation 1].<img file="JP4068366B2_D0001.tif" />It can be obtained as each coordinate (x, y) from the calculation formula of.

Further, since the mouse coordinate calculation on the personal computer screen is required on the personal computer, the coordinate calculation for specifying the mouse cursor position is performed (step: S125). That is, assuming that the mouse coordinates are (X, Y), these coordinates can be obtained from the formula of X = a11x + a12y + b1Y = a21x + a22y + b2. Here, the coefficients a11, a12, a21, a22, b1 and b2 of the coordinate transformation shall be determined in advance by calibration as an internal configuration.

Next, a process of moving the mouse cursor is performed based on the mouse coordinates (X, Y) obtained by the above (step: S125) (step: S126). After that, the desired coordinate input can be performed by repeating the processes (step: S120) to (step: S126). For example, general-purpose application software such as a paint brush can be used to actually represent the trajectory of the pen on the computer screen. In addition, the characters written on the paper by handwriting are stored in the personal computer as bitmap data.

(Appendix 1) It has a pen that transmits ultrasonic waves and a receiver that receives ultrasonic waves transmitted from the pen with a plurality of ultrasonic receivers, and each ultrasonic receiver of the receiver has. It is a coordinate input device that inputs the coordinate position of the pen based on the propagation time of the received ultrasonic waves, and the receiver is a plurality of ultrasonic receivers that receive the ultrasonic waves transmitted from the pen. A coordinate input device comprising: a holding means for holding a corner portion of a predetermined sheet.

[Appendix 2] The coordinate input device according to Appendix 1, wherein the holding means is fixed to a flat plate on which a paper for writing is placed by the pen.

(Appendix 3) The pen has an infrared transmitter that emits an infrared pulse, and the receiver further includes an infrared receiver that receives an infrared pulse transmitted from the infrared transmitter as a synchronization signal. The coordinate input device according to Appendix 1 or Appendix 2, characterized in that.

(Appendix 4) The receiver fixes the paper at a position where the angle between the straight line connecting the plurality of ultrasonic receivers and the upper side of the paper is in the range of 30 to 60 degrees. The coordinate input device according to Appendix 1, 2 or Appendix 3, which is a feature.

(Appendix 5) On the holding surface of any of the first and second holding means with respect to the paper, an edge portion set to an orientation of approximately 90 degrees is formed so that the corners of the paper can be abutted against each other. The coordinate input device according to any one of the appendices 1 to 4, characterized in that the coordinates are input.

(Appendix 6) When the arrangement interval between the pair of ultrasonic receivers is W and the diagonal length on the paper which is the writing range by the writing means is P, the arrangement interval W of the receivers is 0.0002. P²Greater than 0.002P²The coordinate input device according to any one of Supplementary note 1 to 5, wherein the coordinate input device is set to be smaller than the above.

(Appendix 7) Appendix 1 is characterized in that the maximum sensitivity direction of the ultrasonic receiver is set so that the angle formed by the upper side of the writing range on the paper is in the range of 30 degrees to 60 degrees. The coordinate input device described in any one of ~ 5.

[Effect of the Invention] As described above, according to the invention of claim 1, the receiver includes a plurality of ultrasonic receivers for receiving ultrasonic waves transmitted from a pen, and a predetermined paper corner. Since it has a holding means for holding the portion, a blind spot of the receiver does not occur, it is possible to prevent the apparent interval of the receiver from becoming narrow, and the receiver can be arranged and fixed at the corner of the paper. Therefore, the configuration of the coordinate input device can be miniaturized, and the operability and portability are good, and it is possible to use it as a portable device.

[0069] Further, according to the invention of claim 2, since the holding means is fixed to the flat plate-shaped board on which the paper for writing is placed by the pen, the receiver is previously attached to the corner of the board by the holding means. Since it is placed and fixed in, there is no blind spot in the receiver, it is possible to prevent the apparent spacing between the receivers from becoming narrower, and the board on which the paper is placed functions as an underlay, so when writing. It has the effect that it has good operability and portability and can be used as a portable device.

[0070] Further, according to the invention of claim 3, the pen has an infrared transmitter that emits an infrared pulse, and the receiver receives an infrared receiver that receives the infrared pulse transmitted from the infrared transmitter as a synchronization signal. Since it is equipped with a device, it has the effect of being able to transmit an infrared pulse synchronization signal to the receiver without connecting the pen by wire.

Further, according to the invention of claim 4, the receiver is located at a position where the angle formed by the straight line connecting the plurality of ultrasonic receivers and the upper side of the paper is in the range of 30 degrees to 60 degrees. Since the paper is fixed, there is no blind spot in the receiver, it is possible to prevent the apparent spacing between the receivers from becoming narrower, and it is easy to operate and portable, and it can be used as a portable device. It works.

[0072] Further, according to the invention of claim 5, on the holding surface of any of the holding means with respect to the paper, an edge portion set to an orientation of approximately 90 degrees is formed so that the corner portion of the paper can be abutted against the paper. Therefore, by inserting the paper along the edge, the receiver can be automatically placed at a 45-degree tilt position, which is the maximum directivity, with respect to the paper, further reducing the price. It has the effect of being able to do it.

BRIEF DESCRIPTION OF THE DRAWINGS [FIG. 1] FIG. 1 is a diagram for explaining an overall configuration which is an application example of the coordinate input device according to the first embodiment.

FIG. 2 is a diagram for explaining the arrangement of receivers.

FIG. 3 is a diagram for explaining a configuration of a receiver (top view, front view, side view).

FIG. 4 is a diagram for explaining a paper holding procedure by a receiver.

FIG. 5 is a diagram for explaining the arrangement of receivers.

FIG. 6 is a diagram for explaining the orientation of the receiver.

FIG. 7 is a diagram for explaining the details of the arrangement and orientation of the receiver.

FIG. 8 is a diagram for explaining the maximum sensitivity direction of the receiver.

FIG. 9 is a diagram for explaining experimental results, which is a diagram showing the relationship between distance and error.

FIG. 10 is a diagram for explaining an internal configuration of a dedicated pen.

FIG. 11 is a diagram for explaining an internal block of a drive circuit unit.

FIG. 12 is a diagram for explaining an overall configuration which is an application example of the coordinate input device according to the second embodiment.

FIG. 13 is a diagram for explaining the overall configuration of a coordinate input device in which a receiver and a clip are separate bodies.

FIG. 14 is a diagram for explaining an example of an internal block diagram which is an electric circuit portion of a receiver.

FIG. 15 is a diagram illustrating a waveform (timing chart) of an ultrasonic pulse received by an ultrasonic receiver.

FIG. 16 is a processing flowchart of a microprocessor and personal computer software.

FIG. 17 is a diagram illustrating a configuration of a conventional coordinate processing device.

[Code description] 100,801,805 Coordinate input device 101,803 Receiver 102 Pen 104 Computer 111a, b Input amplifier 112a, 112b Comparer 113a, 113b Zero cross comparator 114a, 114b FF115a, 115b, 710 Timer 116 Microcontroller 304 Ultrasonic receiver 305 Infrared Receiver 307 Edge 704 Ultrasonic Transmitter 705 Infrared Transmitter 711 Infrared Drive Circuit 712 Ultrasonic Drive Circuit 802 Board