JPS60178527A - Identifying method of coordinate - Google Patents

Abstract

PURPOSE:To perform high-precision position detection by calculating coordinates of the tip position of an electromagnetic pen on the basis of the ratio of the difference between induced voltages at both sides of a sense coil where a maximum voltage is induced to the maximum induced voltage. CONSTITUTION:An electromagnetic induction type digitizer has the 1st parallel conductor group 1 and the 2nd orthogonal parallel conductor group 4 connected to a differential amplifier 9 through switch groups 3 and 6. Further, said switch groups 3 and 6 are opened and closed by decoders 10-13. In this case, sense coils are formed while the conductor groups 1 and 4 are sectioned by odd and even numbers, and the switch groups 3 and 6 are also sectioned by respective corresponding groups and opened and closed by said decoders 10-13. Consequently, the position of the electromagnetic pen 14 is detected from induced voltages that sense coils SC generate with magnetic flux from a pen coil 17, and its coordinates are calculated on the basis of the maximum induced voltage and the difference between induced voltages of both adjacent sense coils SC.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a coordinate identification method in an electric conduction type digitizer.

[Prior art]

Figure 1 shows an invention previously proposed by the present inventor (Patent Application No. 58-2).
09882) is a circuit diagram of the %i magnetic conduction type digitizer. In this figure, 1 is the ]th parallel conductor group,
1□+ 12+ 13+ 14+...1p-1
+1p+1p+l+...l It consists of m thousand lines dedicated to lrn.

One end of each of the parallel conductors 11 to 1m is magnetically coupled by a common line 2. In addition, each parallel conductor 1. ~1□The other end is each switch 3 of switch group 3. ,3. .

3. 3. ,...r ap-, la, l 3
p+l 1 . . . 31Tl are connected. 4 has a direction perpendicular to the first parallel conductor #1,
A second group of parallel conductors arranged at equal intervals, 'I+
42+ G* 4. l......

4q-1+ 4q * 4q 10+ +...'l
It consists of one parallel conductor of 4n. 1st. The second parallel conductor groups 1 and 4 are separated by an insulating layer, for example a transparent glass plate or a plastic film. Each parallel conductor 4 of the second parallel conductor #4. ~One end of 4o is common line 5
are electrically coupled by. The common line 2.5 is less susceptible to noise if it is grounded. Second parallel conductor group 4
At the other end are each switch 6116116s of switch group 6.
r 64+...+ 64-1 r 6q *
a, +, 1...6n are connected.

t opposite each parallel conductor of each switch in switch groups 3 and 6
The terminals of illll are the 4Ith and 4J+rth terminals of the first group and 4.ill, respectively. +7th and 4J+5th groups, each of which is connected 11 to the differential amplifier 90 input terminal via a common line 7.8. Here, J is an integer including 0. However, 4J-0 is excluded.

The switches in each group of switch groups 3 and 6 are opened and closed by decoders 10 to 13. In switch group 3 or 6, the first. When one switch in each of the second group is selected and closed, a sense coil with one turn of parallel conductors connected to that switch is formed, and a differential amplifier is formed. Connected to 9.

The selection method for each switch is arbitrary, but the first choice is to select two adjacent G-numbered switches or adjacent 211M even-numbered switches. That is, in switch group 3, 31, 33+32, and 3. , 3. and 33. ...
...3I and 3i+2+ ...+ 3m-2
Close the two switches of the combination of and 3m. Now, fills with one turn formed from parallel conductors are sequentially connected to the sense coil S C1r S C! r...-
3Ci, --SC,, -z. When the tip 15 of the 141 magnetic pen 14 approaches these sense coils SC (no suffix is added when they are collectively referred to), the magnetic flux generated from the pen fill 11 excited by the oscillator 161C interlinks with these sense coils SC. , voltage induced sense fill 5Ci-+ + SCi r SCI+1
Let the induced voltages of -1 and ν++vi++ be respectively.

Switch group 6 also selects 4>MK and closes.

The induced voltage in the sense coil SC is detected by the differential amplifier 9 and applied to the signal processing circuit 18. I^ processing circuit 18
sends signals to decoders 1o to 13, and switches group 3,
6 is selected and closed, and the induced voltage of each sense coil SC is measured and processed. When the ID number processing circuit 18 measured the maximum voltage, the signal processing circuit 18 sent it to the decoders 10 to 13 (
By comparing No. 1, it is possible to identify which sense coil SC+ has the induced voltage. Incidentally, the IH@processing circuit 1B can be configured using a rectifier circuit, an A/D converter, a micro-pull sensor, and a counter.

The tip of the electromagnetic pen 14/1ii15 is the above sense coil SC
When the tip 1 of the electromagnetic bend 14 is located at the tip 1 of the electromagnetic bend 14, the induced voltage of the sense coil SCi becomes maximum.
5 is located on which sense file sc. 'The detailed tip position fdlx of the electromagnetic vent 14 in the sense file SC+ is determined by the following conventionally known method. However, the direction of X is perpendicular to the first parallel conductor #1, and the position of the center line of the sense coil SCi is set to x=0. Vl(x) or V
-(x) (Vl (xL V-(x) '1 Together, V (x) is taken as a function of

Vl-+ T Vl + VI+ obtained for each X
When V(X+ is subtracted from 1), a curve as shown in Figure 2 is obtained as the relationship between Vlxl and X.

Here, l is the first. This is a conductor pinch in the second parallel conductor groups 1 and 4. The relationship between X and V (x) is stored in It OM, and the value of the coordinate X can be read from the ROM based on the calculation result of equation +11.

The seat 411iX in the entire input panel is determined by the following formula.

″X=iZ+x ・・・・・・・・・・・・・・・・・・
(2) However, the origin of the seat 41X in the entire input panel is the position of the parallel conductor 11.

The coordinates of the direction in which the second parallel conductor group 4 is directly fired can be similarly determined from the induced voltage of the sense fill SC formed from the second parallel conductor group 4.

In the above method, the magnitude tJ4I of Vl-1 and V +
This method has the drawback of having to compare the relationship between the two and selecting a calculation formula based on the comparison results. Since the calculation result of equation (1) is a curved edge as shown in FIG. 2, there is also the drawback that it is difficult to directly obtain the coordinate X by calculation.

[Summary of the invention]

The present invention has been made in view of the above-mentioned points, and the coordinate identification solves the above-mentioned drawbacks by making it possible to use a calculation formula in which the value of the calculation result is proportional to the position of the tip of the electromagnetic pen. The present invention provides a method. Hereinafter, the present invention will be explained in detail with reference to the drawings.

[Embodiments of the invention]

Equation (3) is a calculation formula that can be used in this invention.

V(xl=A(ya+-two)/嘗0・・・・・・・・・
... (3) Here, τ. is sense coil 111I
The maximum value of the electromotive force, ``++'', is the electromotive force of the sense coil adjacent to the sense coil where the maximum value is induced.υ
. When τ corresponds to τ in equation (1), τ−2υ
Each + corresponds to vIi*t11++. A is a constant. Equation (3) is also '@ tip position of magnetic pen 14 1t
It is a function of X. Actually measured 'i-1r ''i + t1
Based on 1+1, wJ131 formula is tit −L, and the obtained V
An example of the relationship between (x) and X is shown in FIG. 3 with A=1. In this way, Equation (3) becomes a straight line passing near the origin. That is, x=BV(xJ=AB(y+ 11-)/v6 ---
(Can be expressed as 41. Therefore, for example, 416, 11-, 11 when x = l / 2
If A is determined so that the calculation result of equation (3) using + is equal to l/2, B=1, that is, x=VlxJ.

First, an example of inclusion of #gl will be explained.

(1) Set A=1, store the relationship between V (xJ and X in FIG. 3 in memory, and access this memory by L.

Add a child of approximately 6 to the calculated V (lx).

Set A so that +218=1,! Calculate X directly from formula 441.

The seat 411X in the entire input panel is determined by the 21st formula in the same way as when determining the coordinates by the +11th formula.

The relationship diagram between V (xl and Accuracy is high when applied when the is not tilted.

FIG. 4 shows an example of a line showing the relationship between the calculated result of equation (3) and X when the electromagnetic pen 14 is tilted with respect to the plane of the sense coil SC.

Here, the inclination angle θ of the electromagnetic pen 14 is the sense coil I'
11] and the electromagnetic pen 14. Line ii 19 is an example of the calculation result when the magnetic pen 1a 14 is tilted and the straight line 20 is not tilted. straight#
Q20 is the same as in FIG. If the electromagnetic pen 14 is thin, the line will be deviated from the origin O, like a straight line 19. The degree to which the electromagnetic pen 14 deviates from the zero point is determined by the 0 inclination angle of the electromagnetic pen 14.
The conductor pitch of the first half-lamp conductor group 1.4, the distance between the sense fill SC and the electromagnetic pen 14, etc. vary depending on K.

? When holding tt&fmtit4 in your hand to increase the weight of the vehicle,
It can tilt up to about 40 degrees. The straight line 19 is assumed to be - when the electromagnetic pen 14 is tilted in the X direction at θ=40°. When writing with the electromagnetic pen 14 always tilted in the direction of X, the accuracy is even worse if X is calculated from the relationship between Vlxj and X represented by the straight line 19.

However, the tilt angle θ of the TFT1111 pen 14 changes depending on how it is held, and the tilt angle θ with respect to each sense coil SC also changes depending on the orientation of the electromagnetic pen 14 with respect to the parallel conductor group 1 or 4. Even if you calculate X based on the calculation result of V (×1) regarding 0, you cannot always obtain the sieve degree.
If the gradients are not the same, at the boundary where the sense coil SC where the maximum electromotive force is generated moves to the adjacent sense coil SC as the electromagnetic hexagon 14 moves, the sense coil that generates the maximum fermentation pressure is moved to the right side. The value of X obtained differs depending on whether the sense coil is used or the left sense coil is used, and of course w1. ability becomes worse. That is, in the straight line 19, V (X when xi becomes BiI3.-BiI3
When the values of are respectively + and -, and the sense coil inevitable pressure is equal and maximum in the sense coils SC+ and SC1+, the sieve electromotive voltage of the sense coil SΩ is V
. The coordinate X that can be reached when is Xl = i l
10+, and when the disturbance voltage of the sense coil SC1++ is υ0, the seat [X+++ is X++1 = (i+1)! + becomes -, but when k0~ is -, it becomes X+ 4 X++1, which is discontinuous. The magnitude of the deviation δ between the curvature and X1+ is δ'' k+ 10-. It is necessary to make this deviation as small as possible to improve the resolution.

The straight line 21 in FIG. 4 is the V (yll) of the table line that represents the relationship between xl and X, which is effective for reducing the above-mentioned δ.

Straight line 21 is between straight lines 19 and 20. That is, V(
xl is B172. -More than BiI3+7 on m21)
Point f7) If the 1st position of X is S+ and 8-, then k-
<S-<-1/2 and +<S+<-1/2. @Ume21 When calculating the locus g4X from the calculation result of V If k + 10l/2)/2, then δ=S-+S+ = (k-10+)/2, which is half the difference when calculating the coordinate X using straight line 19, tl, and the resolution is improved. At this time, V (
The coordinate X determined using the calculated value of xi and the straight line 21 is given by the seated image X &i of the entire input surface in equation (2).

Substituting equation (3) into equation (5), in equation (6), (S+ S-) A/ B l
, (S++8-)/2 is a constant, so if we determine this in advance and set them as C and D, the coordinates X
is determined by the following formula.

Calculating the coordinate X using equation (6) or equation (7) is
This is another embodiment of this invention.

When the coordinate When using the force formula, unless the electromagnetic pen 14 is tilted, it is natural that the resolution is larger and the resolution is worse than when using the formula (3) or (7). However, during writing, the tilt angle θ of the city pen 14 varies from 0° to about 4°.
Because it changes at any time up to 0°, the maximum value of the error is small no matter how the tilt angle θ changes, and the degree of deterioration of resolution is small for straight line 21. This is when formula (7) is used.

In the above, S-(k--1/2. S+(k+
+l/2)/2 has been explained, but in the case of lul between S+ crab ten and -172, and between S+ crab ten and l/2, the accuracy 1 resolution iIb is better than when using 1 section line 19. good.

In addition, in the above, the circle 19 is a line showing the measured red of formula (3) when the inclination angle θ of the electromagnetic pen 14 is 40 degrees, but this is the maximum inclination that can be assumed during writing. This shows an example of the angle, and it goes without saying that the gt Et results obtained when the tl mound angle θ is increased or decreased as necessary may be applied.

In addition, in the above explanation, the case where the tip position of the electromagnetic pen 14 is licked in the ui magnetic visit type digitizer shown in FIG. 1 has been explained. 41 methods to choose
The present invention can be applied to a magnetic vj-specific digitizer or to a digitizer of other configurations.

〔Effect of the invention〕

As explained above, the first and second aspects of the present invention are based on the induced voltage of the two sense coils on both sides of the sense coil where the maximum induced voltage is generated, and the maximum induced voltage. Since the ratio of the electromagnetic pen is set to 'Ik4' and the seated image of the tip position of the electromagnetic pen is calculated, the calculation formula becomes 11 lines passing through the origin, so the induced voltage of the sense coils on both sides of the sense coil that generates the maximum induced voltage is There is no need to compare the magnitude of , and therefore there is no need to select a calculation formula.

In addition, Kaimei of the second examiner further determined that the value of the rIil writing ratio at the inclination angle θ of the I41m pen and the value of the previous Iil writing ratio at the assumed maximum writing angle of 1 of the electromagnetic pen,
I made it possible to find the coordinates of the tip of the electromagnetic pen using the line that represents the relationship with the coordinates of the tip of the electromagnetic pen, so 'ill
(It has the advantage of being able to perform highly accurate IR detection regardless of the M pen.

Furthermore, the 1st and 2nd K? It is also possible to determine the coordinates directly by calculation without using memory.
Therefore, when the seated statue is installed with this invention,
This has the advantage that peripheral circuits and firmware can be made into a simple IIF.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an example of an electric #ii, iAi 4 type digitizer to which this invention is applied, and Fig. 2 is a diagram showing the relationship between the measuring system and the sitting image Figure, k
Diagram N3 and Diagram 1j44 are diagrams showing the connection between the subtraction formula and the coordinate X applied in this invention. In the figure, 1 is the first parallel conductor group, 2. 5. ? , 8 is a common line, 3 and 6 are switch groups, 4 is a second conductor group, 9
The difference is yIJJ multiplier, 10 to 13 are Tekota, 14 is electromagnetic pen, 15 is the tip, 16 is generator, 11 is Pen coil, 18 is No. 4.3 processing circuit, 19 to 21 is Jansfeil general electromotive voltage This is a straight line that shows the relationship between the total of q4 tatami and the seat 44x. Figure 1'' Figure 2-I72 172 Figure 3

Claims (1)

[Claims] il+ An electromagnetic pen for generating an alternating magnetic field, a plurality of sense coils that induce an electromotive force due to the linkage of magnetic flux generated from the electromagnetic pen, and a switch for selecting the sense coils. 1- Identify the tip position of the previous magnetomotive magnetic pen by detecting the induced voltage of the sense coil.
In an electromagnetic induction type digitizer, which consists of a circuit for generating a maximum induced voltage, the ratio of the difference in induced voltage between the two sense coils on both sides of the sense fill where the maximum induced voltage is generated and the maximum induced voltage is calculated. A coordinate identification method characterized in that the coordinates of the tip position of the electromagnetic pen are determined by (2) An electromagnetic pen for generating an alternating magnetic field, a plurality of sense fills that induce an electromotive force due to the linkage of magnetic flux generated from the electromagnetic pen, a group of switches for selecting the sense coil, and the sense coil for selecting the sense coil. In a flit magnetic induction digitizer, which includes a circuit for identifying the position of the tip of the electromagnetic pen by detecting the induced voltage in the coil, two sense coils on both sides of the sense coil where the maximum induced voltage is generated are used. Based on the ratio between the difference in induced voltage of the coil and the maximum induced voltage, 8i at the tilt angle of the electromagnetic pen
A direct bullet representing the relationship between the value of the J writing ratio and the ratio at the assumed maximum inclination angle of the 111 '4 magnetic pen and the coordinates of the tip position of the electromagnetic pen. A coordinate identification method characterized in that the coordinates of the tip position of the electromagnetic pen are determined using the electromagnetic pen.