JPS61105633A - Coordinate detecting method - Google Patents

Abstract

PURPOSE:To improve the coordinate value detecting accuracy by adding a confirming process for confirming a fact that an equivalent human body capacity formed through a finger touched with a coordinate input panel in the course of measurement is invariable. CONSTITUTION:X axis scanning switches 12, 13 are selected, a buffer circuit 3 and a coordinate input panel 11 are pronght into contact with one direction by using a polarity inverting analog switch 4, an output X0 of a digital oscillator 5 is measured, the buffer circuit 3 and the coordinate input panel 11 are pronght into contact with the opposite direction by using the polarity inverting analog switch 4, and an output X1 of the digital oscillator 5 is measured. Subsequently, Y axis scanning switches 14, 15 are selected, the buffer circuit 3 and the coordinate input panel 11 are connected to one direction, an output Y0 of the digital oscillator 5 is measured, and subsequently, the buffer circuit 3 and the coordinate input panel 11 are connected to the opposite direction by using the polarity inverting analog switch 4, and an output Y1 of the digital oscillator 5 is measured. From calculating an expression, XS and YS are compared, whether its difference is within a specified range or not is decided, and a coordinate value of a point to which a finger has been touched is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coordinate power method. In particular, the coordinate detection force method using the finger touch detection force type coordinate detection device using the coordinate impedance conversion method related to the earlier application filed by the present applicant (Japanese Patent Application No. 511-'37914), This invention relates to an improvement that makes it possible to detect highly reliable coordinate values by adding a procedure for determining the validity of detected values.

[Conventional technology]

The present applicant has invented a finger touch detection force type coordinate detection device using a coordinate impedance conversion method based on the following principle.

An AC voltage V is applied to both ends of a linear resistor l having a resistance value R shown in FIG. 2, and a point ,
Grounded through capacitor 2, current I is applied to the left side of resistor l.
Current ■2 is applied to the right side of L, and the potential at point X is V. If the resistance from the left end of resistor 1 to point X is Rx, and the resistance from point X to the right end of resistor I is R(1-x), then Therefore, the coordinate X of point X can be detected as.

Similarly, as shown in Fig. 3, the linear resistor l is
A buffer 3 whose input impedance is infinite, whose output impedance is zero, and whose amplification factor is 1"1 is short-circuited, and an AC voltage is applied to the input terminal of this buffer 3. Then, the linear resistor 1 and An analog switch 4 is provided between the buffer 3 and the buffer 3 so that the polarity can be reversed.

First, connect the analog switch 4 as shown in the figure, connect the input end of the buffer 3 to the left end of the linear resistor 1, connect the output end of the buffer 3 to the right end of the linear resistor 1, and Impedance X, without any point of resistor 1 being grounded with human body capacity 2. Next, invert the analog switch 4, connect the input end of the buffer 3 to the right end of the linear resistor l, connect the output end of the buffer 3 to the left end of the linear resistor 1, and measure the impedance. Measure x1.

Next, touch a point X a distance X from the left end of the linear resistor l and ground it through the human body capacitor 2.
Perform the same operation as above to set the impedance X. ×, x
Measure ix.

Using the numbers above, The coordinate values of point X can be determined using the following formula.

Therefore, the linear resistor is replaced with a sheet resistor 1 as shown in FIG.
1, and if an X-axis direction operation switch 12.13 for detecting the coordinate in the X-axis direction and a Y-axis direction operation switch 14.15 for detecting the coordinate in the Y-axis direction are provided, a one-plane resistor can be obtained. The X and Y coordinates of any point on the body 11 can be detected. Note that 1B.

17 is a changeover switch for X coordinate detection, to,
ts is a changeover switch for detecting the Y coordinate, and 3 and 4 are the same buffers and polarity inversion analog switches as described above.

[Problem that the invention seeks to solve]

However, in the coordinate detection force method using a finger touch detection force type coordinate detection device using the coordinate impedance conversion method described above, the finger touch pressure cannot be measured while measuring impedance with the finger touch. It is difficult to keep it constant, and therefore the capacitance between the finger and the linear resistor 1 or the sheet resistor 11 tends to change, and eventually the 1 equivalent human body capacity changes, resulting in coordinate value detection error. It is the cause of

[Means for solving problems]

The present invention eliminates this drawback and provides a finger touch detection force type coordinate detection device using a coordinate impedance conversion method with high coordinate value detection accuracy, and its means include:
a coordinate input panel made of a rectangular sheet resistor; means for connecting an impedance element to an arbitrary point on the coordinate input panel; An X-axis scanning switch and a Y-axis scanning switch that sequentially form conductive paths between the regions, a buffer circuit having an extremely large input impedance and an extremely small output impedance and an amplification factor of about 1, and the buffer circuit described above. The impedance defined by the changeover switch connected to each of the X-axis scanning switch and the Y-axis scanning switch sequentially and with changing polarity and the buffer circuit is inputted, and a constant quantitative relationship is established with the impedance. The buffer circuit is connected to one direction of the X@ direction of the coordinate input panel, and the scan switch is used to scan and detect the output of the electric circuit. Output X. , connect the buffer circuit to the opposite direction of the X-axis direction of the coordinate input panel, scan using the scan switch to measure the output x1 of the electric circuit, and connect the buffer circuit to the coordinate input panel. Connect in one direction of the Y-axis direction of the panel,
The scan switch is used to scan the output Y of the electrical circuit. , connect the buffer circuit in the opposite direction of the Y-axis direction of the coordinate input panel, scan using the scan switch to measure the output Y1 of the electric circuit, and With the impedance element connected to the point, the buff 77 circuit is connected to one direction of the X-axis direction of the coordinate input panel, and the output xoX of the electric circuit is measured by scanning using the scanning switch. , with the impedance element connected to an arbitrary point on the coordinate input panel, the buffer circuit is connected in the opposite direction of the X-axis direction of the coordinate input panel, and the scan switch is used to scan the Measure the output x1X of the circuit, connect the impedance element to any point on the coordinate input panel, connect the buffer circuit in one direction of the Y-axis direction of the coordinate input panel, and use the scan switch. scan and measure the output Y0X of the electric circuit, and in a state where the impedance element is connected to an arbitrary point on the coordinate input panel,
The buffer circuit is connected to the opposite direction of the Y-axis direction of the coordinate input panel, the output Y1Y of the electric circuit is measured by scanning using the scan switch, and the impedance element is connected by calculating In the method of detecting the coordinates of a point.

X =X −X +X1x−X1s ox
.

It is a coordinate detection power method that calculates YS ``YOY-YO+Y1Y-Y1 and performs a ball detection operation to confirm that the difference between X and YS is within a specific range.

(Function) As mentioned above, the cause of the error in the finger touch detection force type coordinate detection device using the coordinate impedance conversion method is that the capacitance of both human bodies changes during the measurement of impedance with the finger touching. Therefore, if the human body capacity changes during measurement, if there is an index that changes to follow this change, and if the measurement is performed while checking this index, the above error will not occur. It should be possible to avoid it.

By the way, xS"xOX-xO+xIX-x1 and YS"YOY-YO+Y1Y-Y1 are I4! If the impedance of each area of the standard input panel is uniform and the shape is square, originally they should be exactly the same. If the coordinate input panel has a rectangular shape, the difference should be a fixed value. Therefore, the coordinate detection operation is performed by comparing X and Ys and confirming that the difference is within an allowable range. If the difference is not within an acceptable range, it is necessary to re-perform the corresponding measurement process.

(Example) A coordinate detection device according to an embodiment of the present invention will be further described below with reference to one drawing.

Reference numeral 11 in FIG. 1 is a coordinate detection panel made of a planar resistor. 1
2.13 is an X-axis scanning switch and a 9-coordinate detection panel! (2) It is used to sequentially form conductive paths between mutually opposing points along the mutually opposing sides. 3 is a buffer whose input impedance is infinite, whose output impedance is zero, and whose amplification factor is approximately l. 4 is an analog switch for reversing the connection polarity between the coordinate detection panel II and the buffer 3;
Used to switch from left to right and right to left, top to bottom and bottom to top. 5 is a digital oscillator which receives impedance from the buffer circuit 3 and detects the oscillation frequency. 6 is MPtJ that controls this coordinate detection device, and in Figure 1, it is used for scanning in the X-axis direction and
It is said to perform switching with axial direction scanning, control of each axial direction scanning, and control of polarity switching of each axis. 7 is a switching command line for scanning in the X-axis direction, 8 is a switching command line for scanning in the Y-axis direction, and 9 is a command line for polarity reversal.

To perform coordinate detection using the coordinate detection device having such a configuration, first, select the X-axis scanning switch 12, 13, and use the polarity reversal analog switch 4 to connect the buffer circuit 3 and the coordinate input panel 11. Connect in one direction.

The output (oscillation period) x0 of the digital oscillator 5 is measured.

9 Next, use the polarity reversal analog switch 4 to connect the buffer circuit 3 and the coordinate input panel! 1 in the opposite direction, and measure the output (oscillation period) xl of the digital oscillator 5.

C. Thirdly, select the 7-axis scanning switch 14, 15 and use the polarity reversal analog switch 4 to select the buffer circuit 3.
and the zakeyaki input panel 11 are connected in one direction, and the output (oscillation cycle) Y0 of the digital oscillator 5 is measured.

Second, fourth, the buffer circuit 3 and coordinate input panel using the polarity reversal analog switch 4! 1 in the opposite direction, and measure the output (oscillation period) Yl of the digital oscillator 5.

Ho, here.

xS ”xOX-xO+xIX-x1 Ys ”Yov-Yo +Ytv-Yt is calculated and xs
and Ys are compared, and it is determined whether the difference is within a specific range. And if.

If it deviates from a specific range, the above measurement is performed again.

After confirming that the difference between x, and Y8 is within a certain range.

is calculated to detect the coordinate value of the point touched by the finger.

〔Effect of the invention〕

As explained above, according to the present invention, in the coordinate detection force method using a finger touch detection force type coordinate detection device using the coordinate impedance conversion method, the Since a confirmation step is added to confirm that the formed equivalent human body capacity remains unchanged, it is possible to provide a coordinate detection power method with high coordinate value detection accuracy.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a finger touch detection force type coordinate detection device using a coordinate impedance conversion method used in a coordinate detection force method with high coordinate value detection accuracy according to an embodiment of the present invention. 2 and 3 are principle diagrams illustrating the principle of a finger touch detection force type coordinate detection device using a coordinate impedance conversion method. FIG. 4 is a principle diagram of a finger touch detection force type coordinate detection device using a coordinate impedance transformation method used in the coordinate detection force method with high coordinate value detection accuracy according to the present invention. 1.11...--Coordinate detection panel consisting of a sheet resistor. 12.13・Fist・X wheel direction scanning switch, +4.15・
-Y-axis direction scanning switch. 1B, 17...Switch switch for X coordinate detection,
18.1fl--・Switch switch for Y coordinate detection,
2-Φ fist capacitor, 3 @ conflict buffer, 4
-Analog switch, 5...9 oscillator, 6.Fist, MPU, 7...X-axis direction scanning switching command line, 811...Y-axis scanning switching Fig. 2 Fig. 3

Claims (1)

[Claims] A coordinate input panel made of a rectangular sheet resistor, means for connecting an impedance element to an arbitrary point on the coordinate input panel, and means for connecting an impedance element to an arbitrary point on the coordinate input panel, and an X-axis scanning switch and a Y-axis scanning switch that sequentially form conductive paths between regions that are present and facing each other; a buffer circuit that has an extremely large input impedance, an extremely small output impedance, and an amplification factor of approximately 1; A changeover switch connects the buffer circuit to each of the X-axis scanning switch and the Y-axis scanning switch sequentially and with changing polarity, and an impedance defined by the buffer circuit is inputted to the impedance. and an electric circuit that outputs an output having a certain quantitative relationship, the buffer circuit is connected to one direction of the X-axis direction of the coordinate input panel, and the scan switch is used to scan the coordinate detection device. to measure the output X_0 of the electric circuit, connect the buffer circuit to the opposite direction of the X-axis direction of the coordinate input panel, and measure the output X_1 of the electric circuit by scanning using the scan switch. , connect the buffer circuit in one direction of the Y axis direction of the coordinate input panel, scan using the scan switch to measure the output Y_0 of the electric circuit, and connect the buffer circuit to the Y axis direction of the coordinate input panel. The buffer circuit is connected in the opposite direction in the axial direction, the output Y_1 of the electric circuit is measured by scanning using the scan switch, and the impedance element is connected to an arbitrary point on the coordinate input panel. is connected to one direction of the X-axis direction of the coordinate input panel, scans using the scan switch to measure the output X_0_X of the electric circuit, and connects the impedance element to an arbitrary point of the coordinate input panel. In this state, the buffer circuit is connected to the opposite direction of the X-axis direction of the coordinate input panel, and the scan switch is used to scan and measure the output X_1_X of the electric circuit. With the impedance element connected to the point, the buffer circuit is connected to the Y point of the coordinate input panel.
The buffer circuit is connected to the opposite direction of the Y-axis direction of the coordinate input panel, and is scanned using the scan switch to obtain the output Y_1_Y of the electric circuit.
Measure X=(X_0_X-X_0)/(X_0_X-X_0+
X_1_X-X_1)Y=(Y_0_X-Y_0)/(
X_S=X_0_X-X_0+X_1_X-X_1Y_
A coordinate detection method that calculates S=Y_0_Y-Y_0+Y_1_Y-Y_1 and performs a detection operation after confirming that the difference between X_S and Y_S is within a specific range.