JPS5935471B2 - Coordinate reader tapelet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention applies an excitation signal to one of the coordinate lines provided on the coordinate indicator or the tablet, and thereby induces a guiding signal to the other one, thereby controlling the coordinate indicator. The purpose of this invention is to improve the guiding efficiency of the excitation signal by folding the coordinate line on the tablet multiple times in a coil shape in a coordinate reading device that detects the coordinate position of the tablet.

Conventionally, all the coordinate lines on the tablet in electromagnetic induction type tablet coordinate reading devices that have been put into practical use have been a single line or a U-shaped pattern.

Therefore, in this case, the coupling coefficient between the excitation section and the induction section is small, and the obtained induction signal level is very low. This causes various noise levels generated when transmitting or amplifying the guidance signal to occupy a high proportion of the guidance signal level, making highly accurate position detection impossible. Therefore, in the present invention, the shape of the coordinate line is folded multiple times to form a coil wound multiple turns on the same axis to increase the coupling coefficient between the excitation part and the induction part, thereby obtaining a high-level induction signal and reducing the noise level ratio. This makes it possible to make a stable and highly accurate coordinate reading device relatively small.

Embodiments of the present invention will be described in detail below based on the drawings.

Fig. 1 shows an example of a tablet according to the present invention. Coordinate line sx consisting of a plurality of coiled conducting wires
1-sxn and sy1 to syn are arranged at equal intervals, and scanning circuits 4 and 5 are provided for applying a scanning excitation signal consisting of a scanning signal and an excitation signal to each coordinate wiring. Figure 2 shows the coordinates sx1 to sxn, syl in Figure 1.
It is a circuit diagram electrically showing the relationship between ~Syn and scanning circuits 4 and 5 in detail.

In the figure, one end of coordinate lines 5
, 5. One end of the coordinate lines passing through this switching element S is all commonly connected to the other end of the power source 6. The scanning signal distributors provided in the scanning circuits 4 and 5 sequentially and sequentially distribute scanning signals to the gate circuits G corresponding to the addresses of the address signals on a one-to-one basis using scanning address signals Ax and Ay that change sequentially and sequentially. One end of the input of this gate circuit G is commonly connected to an excitation signal generator 7 that generates an excitation signal Ex with a sufficiently higher period than the scanning signal, and the scanning signal applied to the other end of the input of the gate circuit G is applied. The excitation signal is passed for the specified time. Therefore, the output of this gate circuit G becomes a scanning excitation signal, and the switching element S opens and closes in synchronization with this scanning excitation signal, and coordinate lines Sxl to Sx correspond one-to-one to the addresses of the scanning address signal.
Scanning excitation signals S, ~ in sequential order in n, syl ~ Syn
Apply Sn. FIG. 3 is a block diagram of the entire apparatus for explaining the principle of X-axis coordinate reading operation of the coordinate reading apparatus according to the present invention.

In the figure, reference numeral 8 denotes a scanning address signal generating circuit consisting of a ring counter or one having an equivalent function, and the addresses of the address signal are sequentially shifted at a constant cycle and inputted to the scanning circuit 4. This scanning circuit 4 applies a scanning excitation signal to the coordinate line SX1, which is in one-to-one correspondence with the address of the scanning address signal. Further, an induction signal induced by the scanning excitation signal applied to the coordinate line is generated in a detection coil provided in the coordinate indicator 9 placed at an appropriate position on the tablet 1.

At this time, at the coordinate position indicated by the coordinate indicator 9, the electromagnetic induction range of the coordinate lines exerted on the detection coil 10 is at least three.
Guide signals with different levels depending on the distance between 0 and the coordinate line are sequentially induced in the order of the scanning excitation signals, and by comparing these guide signals, the coordinate point indicated by the coordinate indicator 9 can be reliably determined. I can do it. Reference numeral 12 denotes a bandpass filter to which the induction signal induced in the detection coil is input, and this bandpass filter 12 removes noise components applied during transmission of the induction signal and outputs only the induction signal. is a rectifier connected to the output side of the bandpass filter 12, which converts the induced signal output from the bandpass filter 12 into direct current, and also converts the sinusoidal induced voltage with respect to the coordinate position into a triangular shape in addition to the curve generator 14. Correct it to a straight line.

15 is an A-D converter that binary encodes the correction signal output from the curve generator 14, and this binary signal, that is,
Position information from the three coordinate lines generated in the detection coil 10 by scanning excitation signals sequentially applied to the coordinate lines is sequentially stored in the register 16, and each piece of information in this register is processed by the comparator 17. The maximum value () is input to the arithmetic circuit 18, and the contents of the register 16 corresponding to before and after the maximum value are further compared, and the scanning signal of whichever is larger is inputted to the arithmetic circuit 18. If the address is smaller than the address of the scanning signal with the maximum value, it is input to the arithmetic circuit 18 as a negative address, otherwise it is positive, and the arithmetic circuit 18 is operated in accordance with both inputs, It is designed to calculate the specified coordinate values.

Next, the operation of the apparatus of the present invention configured as described above will be explained.

The coordinate indicator 9 is now pointing to the coordinate line Sx where the tablet 1 is laid out.
If the scanning excitation signal is placed on an arbitrary coordinate line Sxi among the coordinate lines SXl to Sxn, the scanning excitation signal is applied to the detection coil 10 of the coordinate indicator 9 in order from the smallest number to the coordinate lines SXl to Sxn. A guiding signal is sequentially induced by a scanning excitation signal that is sequentially applied to the coordinate lines SX1 to SX1-2, but this guiding signal is equal to zero because of the distance between the coordinate indicator and the coordinate wiring.

Next, an induction signal is induced by the scanning excitation signal applied to the coordinate line Sxi-1, and when the scanning excitation signal application time to the coordinate line Sxi-1 has elapsed, the scanning excitation signal is applied to the coordinate line SXl, thereby causing the same An inductive signal is induced in the detection coil. The guidance signal level at this time shows the maximum value. Similarly, when the time for applying the scanning excitation signal to the coordinate line Sxi ends, a scanning excitation signal is sequentially applied to the coordinate lines Sxi+1, Sxi+2 to Sxn in this order, and a guiding signal is induced each time.
FIG. 4 is a diagram showing the relationship between the induction signal W1 induced in the detection coil 10 and the excitation signal with respect to the time axis. In the figure, A, b, and c are coordinate lines Sxi-1 and Sxi, respectively.
, Sxi+1, and W1 is an induction signal induced in the detection coil 10 by this. Next, noise components are removed by passing this induction signal through a band filter 12 whose center frequency is the frequency of the excitation signal, and only the induction signal is extracted. After rectifying this induction signal with a rectifier 13, a curve generator 14 Enter.

This curve generator 14 passes the induced voltage level distribution shown in FIG. distance) to a linear distribution. Next, this correction signal is subjected to binary encoding by the AD converter 15, and then stored in the register a. Next, the contents of register a are transferred to register b, and the induced signal due to the scanning excitation signal applied to the next coordinate line is corrected and the binary encoded contents are stored in register a. Furthermore, when the next guidance signal is input, the contents of register b are stored in c, the contents of register a are stored in b, and new data are stored in a. This cycle continues until the contents of register b become larger than the contents of other registers A and c. Therefore, at the end of the above cycle, the coordinate indicator 9 indicates the coordinate line Sx.
i, the registers A, b, and c are used to correct the induction signal induced in the detection coil 10 by the scanning excitation signal applied to the coordinate lines Sxi-1, Sxi, and Sxi+1, respectively, and encode it in binary code. The contents are memorized. In this way, it is the arithmetic circuit 18 that determines whether the maximum value has been stored in register b, and this arithmetic circuit always compares the contents of three registers A, b, and c to determine whether the maximum value is stored in register Continue the above operations until it is memorized. Next, when the maximum value is stored in register b, these registers A and c
are compared by the arithmetic circuit 18, and if the address of the larger scanning signal is smaller than the address of the scanning signal with the maximum value, it is negative, otherwise it is positive, and the coordinate indicator 9 Have the students judge whether it is between the coordinate lines. Therefore, for example, if the position indicated by the coordinate indicator 9 is on the coordinate line Sxi and on the side of the coordinate line Sxi+1, it will be positive, and at this time, the contents of the scanning address signal generation circuit 8 will be positive because it has scanned up to the coordinate line SXl+1. Therefore, 1 is subtracted from this address to make it the address corresponding to the coordinate line Sxi, and this content is set as the upper bit and the comparison circuit 17
Both signals are added in the arithmetic circuit 18 using the signal from the lower bit as the lower bit, and the result is output as an absolute coordinate value in the X-axis direction indicated by the coordinate indicator 9. Note that if the position indicated by the coordinate indicator 9 is on the coordinate line Sxi-1 side, the value will be negative, and the above-mentioned upper bit and lower bit will be subtracted.

In addition, the above operation is performed using coordinate lines Sxl~ arranged in the X-axis direction.
Coordinates Syl~S arranged in the Y-axis direction perpendicular to Sxn
The same process is performed for yn, and the absolute coordinate value in the Y-axis direction is detected.

An embodiment of the coordinate reading device according to the present invention has been described above.

There are other methods of detecting coordinate values based on the phase difference between the induction signal and the excitation signal, but in either case, the ratio of the induction signal level to the noise component directly affects the coordinate reading accuracy.
Therefore, by folding the coordinate line multiple times into a coil shape as in the present invention, it is possible to increase the level of the guiding signal and reduce the influence of noise components on the coordinate reading operation.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an example of a tablet according to the present invention, Fig. 2 is a detailed electric circuit diagram of Fig. 1, Fig. 3 is a block diagram showing the signal processing system of the coordinate reading device, and Fig. 4 is a scanning FIG. 5 is a time chart showing the relationship between the excitation signal and the induction signal on the time axis, and FIG. 5 is a characteristic diagram of the position correction curve generator. 1... Tablet, Sxl~Sxn, syl~
Syn... Coordinate line, 4, 5... Scanning circuit, 8... Scanning address signal generator, 9...
...Coordinate indicator, 11...Coordinate processing circuit.

Claims (1)

[Claims] 1 Multiple conductive coordinate lines laid out on the tablet,
A coordinate indicator that is placed at an appropriate position on the tablet and has a coiled conductive wire, a device that applies an excitation signal to either the coordinate line or the conductive wire, and a device that applies an excitation signal to either the coordinate line or the conductive wire; In a coordinate reading device comprising a coordinate processing circuit that detects the position of the coordinate indicator on the tablet by a guidance signal induced in one of the above, the coordinate line has a coil shape that is folded back multiple times and wound multiple turns on the same axis. A coordinate reading device tablet characterized by: