POSITION DETECTING DEVICE

Abstract: A position detecting device includes a magnetic member composite (120d) which is integrally composed of a pair of insulating substrates with a plurality of long magnetic members sandwiched therebetween and arranged substantially parallel to each other, and two conductive member composites (130b, 130d) each of which is composed of a plurality of conductive members arranged substantially parallel to each other. The conductive members on each of the two conductive member composites (130b, 130d) are connected vertically with the adja­ cent ones, thereby alternately constituting exciting lines (140a-140i) and detecting lines (150a-150h). The device further includes a driving current source for applying an alternating current of a predetermined frequency to each of the exciting lines, a position designating magnetic generator for generating statio­ nary magnetic field, and a position detecting circuit for detecting the position indicated by the position designating magnetic generator by calculation on the basis of the induced voltages which are induced on the detecting lines. The position designated by the position designating magnetic generator is detected on the basis of a change in the magnetic permeability of the magnetic members to which magnetic field is applied by the position designating magnetic generator. A tablet portion has a very small thickness and the position designating magnetic generator is not connected to any portion of the device, whereby its operability is improved, and the device is not likely to be influenced by external induction nor to produce induction noise which would be transmit­ ted outside.

Description: The present invention relates to a device for detecting a position designated by a position designating magnetism generator on the basis of change in magnetic permeability of a magnetic substance to which a magnetic field is applied by the position designating magnetism generator. A conventional position detecting device detects a position which is indicated by a position indicating pen in the following way. A pulse current is applied to one end of a magnetostrictive transmission medium or to the tip of a position indicating pen in order to produce magnetostrictive oscillating waves in the magnetostrictive transmission medium, and the time required for the voltage induced by the magnetostrictive waves to be detected on a detection coil which is provided on the tip of the position indicating pen or on one end of the magnetostrictive transmission medium is measured by a processing unit or the like, so that the position of the position indicating pen may be obtained by calculation. Such a device is comparatively good in detection accuracy but the fact that a cord is required between the pen and the device for delivery of a timing signal an the like between the pen and the processing unit brings about various problems. For example, the operability of the pen is greatly limited; the device is likely to be influenced by induction from other apparatus, thereby causing errors; the pen may be a source of noise generation; and the pen must be held perpendicular to the magnetostrictive transmission medium and brought into close proximity thereto during operation. In another conventional position detecting device, a plurality of driving lines and detecting lines are arranged orthogonal to each other, a current is applied to the driving lines subsequently, and the induced voltage is detected by subsequently selecting the detecting lines, so that the position designated by a position indicating pen having a magnetic member such as ferrite is detected from the position of the detecting line on which a large voltage has been induced. This device dispenses with the need for the position indicating pen to be provided with a cord. However, the resolving power of the coordinate position is determined by the spacing between the lines, and if the spacing is reduced in order to enhance the resolving power, the SN ratio and stability are degraded or, in other words, it is difficult to improve the resolving power. Further, it is difficult to detect a position right over the intersecting points of the driving lines and the detecting lines. Since the position indicating pen must be used in close proximity to the lines, it is not possible to place thicker objects on the input surface during use. The US-A-4 205 199 and the publication by TAKEDA et al: "A NEW DATA TABLET SUPERPOSED BY A PLASMA DISPLAY PANEL" disclose position detecting devices similar to the one described above, wherein the driving lines and detecting lines for one coordinate direction are arranged in parallel with each other. EP-A-0 1152 961 which forms prior art pursuant to Art. 54(3) EPC dicloses a position detecting apparatus which has a position detecting section having elongated magnetically permeable bodies and a plurality of exiting lines and detecting lines which are arranged alternatingly at right angles to the magnetically permeable bodies. A driving power source is adapted to apply an AC voltage of a predetermined frequency to the exiting lines. A position designating magnetism generator applies a local magnetic bias to the magnetically permeable bodies. The position designated by the magnetism generator is detected by detecting the voltages induced in the detecting lines. The above-described position detecting devices, in which the driving lines and detecting lines are formed by coils, it is difficult to substantially reduce the thickness of the tablet portion. According to the present invention as defined in claim 1, there is provided a magnetic member composite which is integrally composed of a pair of insulating substrates with a plurality of long magnetic members arranged therebetween substantially parallel to each other, and a plurality of conductive member composites composed of a plurality of conductive members arranged substantially parallel to each other. The tablet portion is formed of the conductive member composites which are placed on the opposite sides of the magnetic member composite in such a manner that the conductive members and the magnetic members are orthogonal to each other, and the conductive members on each of the conductive member composites are connected vertically with the adjacent ones, thereby alternately constituting exciting lines and detecting lines. This arrangement makes it possible to make the tablet portion of this device thinner than those used in the conventional devices. The device is easy to manufacture and enables mass production and, hence, reduction in cost. Furthermore, since the magnetic flux between the exciting lines and the detecting lines changes solely within the magnetically permeable materials, their close connection provides a large detection voltage and a good SN ratio. In addition, this device is not likely to be influenced by external induction or to produce induction noise which would be transmitted to the outside. Since a position can be designated by application of a slight magnetic bias to the magnetically permeable material, it is not necessary to bring the position designating magnetism generator into proximity with magnetic members of said magnetically permeable material, and a high effective read value is obtained. It is also possible to insert the tablet portion between metal sheets other than ferromagnetic materials. In addition, since delivery of a timing detection signal or the like is unnecessary, the position designating magnetism generator can be designed to be a cordless member, thereby improving the operability thereof. The position detecting device may include two magnetic member composites and four conductive member composites. In this case, the two magnetic member composites are overlaid one over the other in such a manner that the magnetic members thereof are disposed in the directions of the X axis and the Y axis, respectively, and two of the conductive member composites are placed on both sides of the overlaid magnetic member composites in such a manner that the conductive members on one composite are disposed in the direction of the X axis and those on the other composite are arranged in the direction of the Y axis. The conductive members on the conductive member composites arranged in the directions of the X and Y axis are respectively connected vertically with the adjacent ones, thereby alternately constituting exciting lines and detecting lines in the directions of the X and Y axis. This device not only has the various advantages mentioned in the preceding paragraph, but also is capable of conducting two-dimensional position detection. According to the invention as defined in claim 6, there is provided a position detecting device including a tablet portion composed of a magnetic member composite composed of two insulating substrates and two sets of a plurality of long magnetic members arranged substantially parallel to each other. The two sets of magnetic members are sandwiched between the substrates in such a manner that one set is disposed orthogonally with respect to the other. This device has the advantages described in the previous paragraph and permits a further reduction of the thickness of the tablet portion. The above and other objects, features and advantages of the invention will become clear from the following description of preferred embodiments, taken in conjunction with the drawings, in which: Fig. 1 is a perspective view of an embodiment of the present invention; Fig. 2 shows a practical arrangement of a tablet portion; Fig. 3 shows the arrangement of a magnetic member composite; Fig. 4 is a perspective view of a magnetic member composite; Fig. 5 is a perspective view of a conductive member composite; Fig. 6 is a characteristic curve of magnetic bias in relation to magnetic permeability; Fig. 7 is a graph showing an example of induced voltage produced on each detecting line in the direction of the X axis; Fig. 8 is an explanatory view of the magnetic flux around the exciting lines; Fig. 9 is an electric circuit diagram showing an example of a driving current source; Fig. 10 is a sectional view of an example of a position designating magnetic generator; Fig. 11 is an electric circuit diagram thereof; Fig. 12 is a block diagram showing a practical arrangement of a position detecting circuit; Fig. 13 shows a modification of the tablet portion; and Fig. 14 shows the arrangement of a magnetic material composite in the modification shown in Fig. 13. Referring first to Fig. 1, which is a partially-cutaway exploded perspective view of an embodiment of the present invention, the reference numeral 100 denotes a tablet portion, 200 a driving current source, 301 and 302 multiplexers, 400 a position designating magnetic generator such as a bar magnet, and 500 a position detecting circuit. The tablet portion 100 is, as is shown in Fig. 2, composed of twelve layers which consist of a shield sheet 110a, magnetic member composites 120a, 120b, conductive member composites 130a, 130b, magnetic member composites 120c, 120d, conductive member composites 130c, 130d, magnetic member composites 120e, 120f and a shield sheet 110b, the twelve layers being laid sequentially on each other in reverse order with the shield sheet 110a on the top. A printed circuit base board is used as the shield sheets 110a, 110b each of which is an insulating sheet 111 of, e.g., a glass epoxy resin with a copper sheet 112 pasted on one side thereof. Each of the magnetic member composites 120a to 120f is, as shown in Fig. 3, formed of a plurality of (eight, in Fig. 3) long magnetic members 121 which are arranged substantially parallel to each other, sandwiched between insulating substrates 122, 123 of, e.g., a glass epoxy resin, and bonded into one body by heat contact bonding or the like, as is shown in Fig. 4. The magnetic member 121 is preferably made of a material which is magnetized only slightly by any magnet brought close to it, that is, a material which has small retentivity and high magnetic permeability (µ), e.g., an amorphous alloy wire having a circular cross section of 0.1 mm in diameter. As an amorphous alloy, for example, (Fe 1-X Co x )₇₅Si₁₀B₁₅ (atomic %) is suitable, wherein x represents the rate of Fe and Co, ranging from 0 to 1. Each of the conductive member composites 130a to 130d is composed of an insulating printed circuit base board 131 of, e.g., a glass epoxy resin with a copper sheet pasted on one side thereof. The printed circuit base board 131 is etched such as to form a plurality of (seventeen, in Fig. 5) conductive members 132 having a land hole at both ends thereof. The magnetic member composites 120a and 120b, 120c and 120d, and 120e and 120f are bonded together by heat contact bonding and other substrates are bonded with and fixed to each other through adhesive sheets. Each of the magnetic members of the magnetic member composites 120a, 120c and 120e is disposed in the direction of the Y axis, and each of the magnetic members of the magnetic member composites 120b, 120d, 120f is disposed in the direction of the X axis, while each of the conductive members of the conductive member composites 130a, 130c is disposed orthogonally with respect to the Y axis, and each of the conductive members of the conductive member composites 130b, 130d is disposed orthogonally with respect to the X axis. Alternatively, the tablet portion may be manufactured by heat contact bonding two magnetic member composites such that the magnetic members of one of the composites are orthogonal to those of the other component; adhering and fixing the printed circuit base board to both outer surfaces of the magnetic member composites; and thereafter with or without forming conductive members by an etching process or the like, forming a group consisting of the shield sheet 110a, the magnetic member composites 120a, 120b and the conductive member composite 130a, a group constituting of the conductive member composite 130b, the magnetic member composites 120c, 120d, and the conductive member composite 130c, and a group consisting of the conductive member composite 130d, the magnetic member composites 120e, 120f and the shield sheet 110b; and further adhering and fixing these groups to each other. The total thickness of the tablet portion is actually about 3 to 5 mm, in Figs. 2 to 5 the tablet portion being enlarged solely in the direction of the thickness. Each conductive member of the conductive member composites 130b and 130d is connected such that each opposing pair is connected at the land holes at one end thereof by through-hole contact, thereby alternately constituting exciting lines 140a to 140i and detecting lines 150a to 150h in the direction of the X axis, which are wound around the magnetic members 121 in the magnetic member composite 120d. The other ends of the exciting lines 140a to 140i on the conductive member composite 130b are connected to the other ends of the adjacent exciting lines 140a to 140i of the conductive member composite 130d, namely, connected in series, and the other ends of the exciting lines 140a and 140i are connected to the driving current source 200. The other end of each of the detecting lines 150a to 150h on the conductive member composite 130b is connected to the multiplexer 301, and the other ends of the detecting lines 150a to 150h on the conductive member composite 130d are grounded in common with each other. Each conductive member of the conductive member composites 130a and 130c is connected such that each opposing pair is connected at the land holes at one end thereof by through hole contact, thereby alternately constituting exciting lines 160a to 160i and detecting lines 170a to 170h in the direction of the Y axis, which are wound around the magnetic members 121 in the magnetic member composite 120c. The other ends of the exciting lines 160a to 160i on the conductive member composite 130a are connected to the other ends of the adjacent exciting lines 160a to 160i of the conductive member composite 130c, namely, connected in series, and the other ends of the exciting lines 160a and 160i are connected to the driving current source 200. The other end of each of the detecting lines 170a to 170h on the conductive member composite 130a is connected to the multiplexer 302, and the other ends of the detecting lines 170a to 170h on the conductive member composite 130c are grounded in common with each other. The driving current source 200 constantly supplies an alternating current (e.g., a sine-wave alternating current) of a predetermined frequency to the exciting lines 140a to 140i and 160a to 160i. The multiplexers 301, 302 selectively supply the output signals from the detecting lines 150a to 150h and 170a to 170h to the position detecting circuit 500 in accordance with a control signal. In this structure, an induced voltage is produced on the detecting lines 150a to 150h and 170a to 170h by electromagnetic induction of the alternating current which flows on the exciting lines 140a to 140i and 160a to 160i. Since this electromagnetic induction is conducted through the magnetic members 121 of the magnetic member components 120a to 120f, the greater the magnetic permeability of the magnetic members 121 is, the greater is the value of the induced voltage. The magnetic permeability of the magnetic members 121 greatly varies in accordance with the magnitude of the magnetic bias externally applied thereto. The degree by which the magnetic permeability changes differs depending upon the composition of the magnetic member employed, the frequency of the above-described alternating current, and whether or not a heat treatment or the like is applied to the magnetic member. It is therefore possible to set the magnetic permeability so that it reaches its maximum when a predetermined amount of magnetic bias is applied to the magnetic members, as shown in Fig. 6. Accordingly, the application of the predetermined amount of magnetic bias to the magnetic members 121, in this case, increases the voltages induced on the detecting lines 150a to 150h and 170a to 170h from the exciting lines 140a to 140i and 160a to 160i. It is here assumed that the position designating bar magnet 400 in Fig. 1 is situated above a position A on the tablet portion 100 which is a distance X s away from the detecting line 150a in the direction X and which is a distance Y s away from the detecting line 170a in the direction Y, with the north pole directed downward and that the predetermined amount of magnetic bias is applied to the magnetic members 121. At this time, induced voltages V₁ to V₈ shown in Fig. 7 are produced on the detecting lines 150a to 150h in the direction X. In the graph shown in Fig. 7, the abscissa represents the coordinate positions X₁ to X₈ in the direction X which correspond to the respective positions of the detecting lines 150a to 150h, while the ordinate represents the value of the induced voltages. The largest (maximum) value among the voltages V₁ to V₈ is obtained when the detecting line is immediately under the position A. Each of the voltages V₁ to V₈ is obtained by the multiplexer 301. Accordingly, if the value of the X-coordinate corresponding to the maximum value of the induced voltage is calculated by the position detecting circuit 500, the X-coordinate value X s of the bar magnet 400 is obtained. There may be various methods of calculating the coordinate value X s . One of them is a method wherein the wave form in the vicinity of the maximum value shown in Fig. 7 is approximated by an appropriate function, and the coordinate corresponding to the maximum value of the function is obtained. For example, when the induced voltages from the coordinate X₃ to the coordinate X₅ are approximated by a quadratic function (shown by the solid line in Fig. 7), the following formulae are formed from the induced voltage on the detecting lines and the coordinate values thereof, where the spacing between each pair of adjacent detecting lines 150a to 150h is assumed to be Δ X. V₃ = a (X₃ - X s )² + b (1) V₄ = a (X₄ - X s )² + b (2) V₅ = a (X₅ - Xs)² + b (3) wherein a and b are constants ( a > 0). Further, the following formulae hold: X₄ - X₃ =Δ X (4) X₅ - X₃ = 2Δ X (5) The formulae (4) and (5) are substituted into the formulae (2) and (3), respectively, and the formulae (2) and (3) are rearranged to obtain the following formula: X s = X₃ +ΔX/2 {(3V₃ - 4V₄ + V₅)/(V₃ - 2V₄ + V₅)} (6) Accordingly, it is possible to obtain the X-coordinate value by delivering the induced voltages V₃, V₄, and V₅ on the detecting lines 150c, 150d, and 150e, respectively, and the coordinate value X₃ (known) of the detecting line 150c to the position designating circuit 500, and calculating the formulae (6). The same X-coordinate value is also obtained when the bar magnet 400 is moved along the Y axis. Induced voltages similar to those shown in Fig. 7 are obtained on the detecting lines in the direction Y, and the Y-coordinate value Y s is obtained by a similar calculation. Since the main purpose of providing the magnetic member composites 120a, 120b, 120e and 120f is to form a passage for the magnetic flux which is produced around the exciting lines, as shown in Fig. 8, for the purpose of obtaining a larger electromagnetic induction therethrough, they can be eliminated. The shield sheets 110a, 110b which are provided for preventing transmittance of external noise to the interior and of induced noise to the exterior can also be dispensed with. It is possible to construct a position detecting device for only one direction ( in the direction X, in this case) by eliminating the magnetic member composites 120a, 120c and 120e and the conductive member composites 130a, and 130c. Referring next to Fig. 9 which is a circuit diagram showing a practical arrangement of the driving current source 200, the reference numeral 201 denotes a function generator, e.g., IC. 8038 manufactured by Intersil, which outputs a sine-wave signal of a predetermined frequency determined by the value of a capacitor C and that of a resistor R. A power driver 202 is composed of an operational amplifier and a current amplifier, and is arranged such as to current-amplify the sine-wave signal and deliver the thus amplified signal to the exciting lines 140a to 140i and 160a to 160i. Fig. 10 is a sectional view of an example of the position designating magnetic generator 400, while Fig. 11 is an electric circuit diagram thereof. In Fig. 10, the referential numeral 401 denotes a pen-shaped container made of a synthetic resin or the like. A bar magnet 402 with a tapered tip is housed at one end of the container 401 so as to be slidable axially with respect to the container 401. A control switch 403 is mounted inside the container 401 so as to face the inner end of the bar magnet 402. A transmitter 404 for transmitting an ultrasonic signal and a battery 405, together with an ultrasonic transmitter 406, are housed at appropriate positions inside the container 401. When an operator holds the container 401 and presses the tip of the bar magnet bar 402 covered with a rubber cover 407 against the input surface, the bar magnet 402 slides so as to turn ON the switch 403, thus activating an oscillation circuit 404a and an amplifier 404b in the transmitter 404, so that a signal which indicates the start of measurement, e.g., a continuous pulse signal of a predetermined frequency, is converted into an ultrasonic signal and transmitted from the ultrasonic transmitter 406. Fig. 12 is a circuit diagram which shows the structure of the position detecting circuit 500. When the above-described ultrasonic signal which indicates the start of measurement is transmitted from the ultrasonic transmitter 406, the ultrasonic signal is received by an ultrasonic receiver 501, amplified and shaped by a receiver 502, and then converted again to the original signal, e.g., the continuous pulse signal of the predetermined frequency, before being delivered to an input buffer 503. When a processing unit 504 recognizes the start of measurement by reading out the measurement start signal from the input buffer 503, the unit 504 delivers a control signal to both a switching circuit 506 and the multiplexer 301 through an output buffer 505 so that the respective induced voltages on the detecting lines 150a to 150h in the direction X are successively input to an amplifier 507. Each of the induced voltages is amplified by the amplifier 507 and rectified by a detector 508 so as to be converted into a DC voltage which is further converted into a digital value by an analog/digital (A/D) converter 509 and is then delivered to the processing unit 504 through the input buffer 503. In the processing unit 504, the induced voltages (digital values) are temporarily stored in a memory 510, and the induced voltage V K having the maximum value (K = 1, 2, ...8) is detected from these stored induced voltages. The processing unit 504 further takes out the induced voltage V K-1 which immediately precedes the induced voltage V K and the induced voltage V K+1 which is immediately subsequent to the voltage V K . Thus, the above formula (6) is arithmetically processed by employing the voltages V K-1 , V K , and V K+1 as the voltages V₃, V₄, and V₅, respectively, thereby obtaining the X-coordinate value. Next, the processing unit 504 delivers a control singal to both the switching circuit 506 and the multiplexer 302 through the output buffer 505 so that the respective induced voltages on the detecting lines 170a to 170h in the direction Y are successively input to the processing unit 504 in order to obtain the Y-coordinate value by a processing operation similar to that described above. The processing unit 504 delivers the thus obtained X-coordinate and Y-coordinate values to a digital indicator (not shown) through an output buffer 511 in order to indicate them, to a computer (not shown) in order to process them, or to a digital/analog (D/A) converter 512 in order to convert them to an analog singal before processing them. It goes without saying that the number of magnetic members, exciting lines and detecting lines is not restricted to the number illustrated in the embodiment. It has been experimentally confirmed that when the spacing of the detecting lines is about 2 to 6 mm, position detection is comparatively good. In addition, the position designating magnetic generator is not limited to a bar magnet, and may be in the form of a sheet, ring, or square, or may be an electromagnet. Fig. 13 shows a modification of the tablet portion 100. The tablet portion 100 is, as is shown in Fig. 13, composed of nine layers which consist of a shield sheet 110a, a magnetic member composite 120g, conductive member composites 130a, 130b, a magnetic member composite 120h, conductive member composites 130c, 130d, a magnetic member composite 120i and a shield sheet 110b, the nine layers being laid sequentially on each other in reverse order with the shield sheet 110a on the top. Each of the magnetic member composites 120g to 120i is formed of a plurality of (e.g., 20) long magnetic members 121a which are arranged substantially parallel to each other, and are sandwiched between insulating substrates 124, 125, of, e.g., a glass epoxy resin with or without an insulating substrate 123 such as an adhesive sheet or a glass epoxy resin interposed therebetween, and are bonded into one body by heat contact bonding or the like, as is shown in Fig. 14. The substrates are bonded and fixed together by heat contact bonding through adhesive sheets. Each of the magnetic members 121a of the magnetic member composites 120g to 120i is disposed in the direction of the Y axis, and each of the magnetic members 121b is disposed in the direction of the X axis, while each of the conductive members of the conductive member composites 130a, 130c is disposed orthogonal to the Y axis, and each of the conductive members of the conductive member composites 130b, 130d is disposed orthogonal to the X axis. Alternatively, the tablet portion may be manufactured by adhering and fixing the printed circuit base board onto both outer surfaces of the magnetic member composites, and thereafter with or without forming conductive members by an etching process, forming a group consisting of the shield sheet 110a, the magnetic member composite 120g and the conductive member composite 130a, a group consisting of the conductive member composite 130b, the magnetic member composite 120h, and the conductive member composite 130c, and a group consisting of the conductive member composite 130d, the magnetic member composite 120i, and the shield sheet 110b, and further adhering and fixing these groups to each other. Each conductive member of the conductive member composites 130b and 130d is connected such that each opposing pair is connected at the land holes at one end thereof by through-hole contact, thereby alternately constituting exciting lines 140a to 140i and detecting lines 150a to 150h in the direction of the X axis, which are wound around the magnetic members 121b in the magnetic member composite 120h. The other ends of the exciting lines 140a to 140i on the conductive member composite 130b are connected to the other ends of the adjacent exciting lines 140a to 140i of the conductive member composite 130d, namely, connected in series, and the other ends of the exciting lines 140a and 140i are connected to the driving current source 200. The other end of each of the detecting lines 150a to 150h on the conductive member composite 130b is connected to the multiplexer 301, while the other ends of the detecting lines 150a to 150h on the conductive member composite 130d are grounded in common with each other. Each conductive member of the conductive member composites 130a and 130c is connected such that each opposing pair is connected at the land holes at one end thereof by through-hole contact, thereby alternately constituting exciting lines 160a to 160i and detecting lines 170a to 170h in the direction of the Y axis, which are wound around the magnetic members 121a in the magnetic member composite 120h, The other ends of the exciting lines 160a to 160i on the conductive member composite 130a are connected to the other ends of the adjacent exciting lines 160a to 160i of the conductive member composite 130c, namely, connected in series, and the other ends of the exciting lines 160a and 160i are connected to the driving current source 200. The other end of each of the detecting lines 170a to 170h on the conductive member composite 130a is connected to the multiplexer 302, while the other ends of the detecting lines 170a to 170h on the conductive member composite 130c are grounded in common with each other. This tablet portion is the same as the example shown in Fig. 2 except for the above-described structure. According to this modification, it is possible to make the thickness of the tablet portion 100 smaller than the example described above.

Claims: A position detecting device comprising: a tablet portion (100) composed of a magnetic member composite (120d) composed of a pair of insulating substrates (122,123) with a plurality of long magnetic members (121), i.e. members made of a material which has small retentivity and high magnetic permeability, sandwiched therebetween and arranged substantially parallel to each other, and two conductive member composites (130b,130d) each of which is composed of a plurality of conductive members (132) arranged substantially parallel to each other, said two conductive member composites being placed on both sides of said magnetic member composite in such a manner that said conductive members and said magnetic members are disposed orthogonally to each other, and said conductive members on each of the two conductive member composites being connected vertically with the adjacent ones thereby alternately constituting exciting lines (140a-140i) and detecting lines (150a-150h); a driving current source (200) for applying an alternating current of a predetermined frequency to each of said exciting lines; a position designating magnetism generator (400) for generating a stationary magnetic field; and a position detecting circuit (500) for detecting the coordinate position indicated by said position designating magnetism generator by sensing voltages induced in each of said detecting lines and calculating said coordinate position on the basis of said induced voltages. A position detecting device according to claim 1, wherein another magnetic member composite (120b,120f) is placed on both outer sides of said conductive member composites (103b,130d) in such manner that the magnetic members of said other magnetic member composite are parallel to those of said magnetic member compositie (120d) which is interposed between said conductive member composites. A position detecting device according to claim 1, comprising two magnetic member composites (120c, 120d) of the type specified in claim 1 and four conductive member composites (130a,130b,103c,130d) of the type specified in claim 1, said two magnetic member composites being overlaid one over the other in such a manner that the magnetic members thereof are disposed in the directions of the X-axis and the Y-axis, respectively, two of said conductive member composites being respectively placed on both sides of said overlaid magnetic member composites in such a manner that the conductive members of one composite (130a,130c) are disposed in the direction of the X-axis and those of the other composite (130b,130d) are disposed in the direction of the Y-axis, and said conductive members on said conductive member composites disposed in the directions of the X- and Y-axis being respectively connected vertically with the adjacent ones, thereby alternately constituting exciting lines (140a-140i,160a-160i) and detecting lines (150a-150h,170a-170h) in the directions of the X- and Y-axis. A position detecting device according to claim 3, wherein two additional magnetic member composites (120a,120b;120e,120f) which are overlaid one over the other in such a manner that their magnetic members are disposed in the directions of the X-axis and the Y-axis, respectively, are placed on both outer sides of said conductive member composites (130a-130d). A position detecting device according to anyone of the claims 1 to 4, wherein a shield sheet (110a,110b) made of a non-magnetic metal is arranged on both outer sides of said conductive member composites. A position detecting device, comprising: a tablet portion (100) composed of a magnetic member composite (120h) essentially consisting of two sets of a plurality of long magnetic members (120a,120b), i.e. members made of a material which has small retentivity and high magnetic permeability, the magnetic members of each set being arranged substantially parallel to each other, and two insulating substrates (124,125) which sandwich said magnetic members therebetween, and four conductive member composites (130a,130b,130c,103d) essentially consisting of a plurality of linear conductive members (132) arranged substantially parallel to each other, said magnetic member composite being arranged such that said magnetic members are disposed in the directions to the X-axis and the Y-axis, respectively, two of said conductive member composites being respectively placed on both sides of said mag netic member composite in such a manner that said conductive members of one of said conductive member composites (130a,130c) are disposed in the direction of the X-axis while the conductive members of the other conductive member composite (130b,130d) are disposed in the direction of the Y-axis, and said conductive members of said conductive member composites disposed in the direction of the X-axis and Y-axis, respectively, being connected vertically with the adjacent ones, thereby alternately constituting exciting lines (140a-140i,160a-160i) and detecting lines (150a-150h,170a-170h) in the directions of the X-axis and Y-axis; a driving current source (200) for applying an alternating current of a predetermined frequency to each of said exciting lines in the directions of the X-axis and Y-axis; a position designating magnetism generator (400) for generating a stationary magnetic field; and a position detecting circuit (500) for detecting the coordinate position indicated by said position designating magnetism generator by sensing voltages induced in each of said detecting lines and calculating said coordinate position on the basis of said induced voltages. A position detecting device according to claim 6, wherein two magnetic member composites (120g,120i) are placed on both outer sides of said conductive member composites in such a manner that said magnetic members are disposed in the directions of the X-axis and Y-axis, respectively. A position detecting device according to claim 6 or 7, wherein a shield sheet (110a,110b) made of a non-magnetic metal is placed on both outer sides of said conductive member composites.

Inventors: TAGUCHI, YOSHINORI, YAMANAMI, TSUGUYA
Applicants: WACOM COMPANY, LTD.
Application year: 1985
Main classification: G06K11
IPC codes: G06F3