JPS5843072A - Cursor type graphic input device using electromagnetic induction type - Google Patents

Abstract

PURPOSE:To realize an electromagnetic induction type graphic input device by cursor driving by converting a detection output into a position data on a sensor accordingly, designating accurately the coordinate position on a tablet. CONSTITUTION:When an operation start command is given, an up-down counter 17 starts an up-control. Thus the electromotive force is induced to a pair of sensors 11a and 11b which are continuous to each other with the approach of a coil 5. These induced electromotive forces e1 and e2 are fed to a level deciding circuit 18 to receive the detection of level. When the levels of the forces e1 and e2 exceed prescribed value, a phase difference-digital conversion is carried out between the output of addition of the force e1 and a 90 deg.-phase shift signal e2' and a reference signal eref. This output of the conversion controls the up-down stoppage in accordance with the overflow, underflow or intra-sensor state respectively. The multiplexers 12 and 13 are switched successively by the output of the counter 17. Finally the counter stops right under the coil 5 and delivers the position data to finish the detection of position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic induction type cursor drive type graphic input device.

FIG. 1 is a block connection diagram showing this cursor drive type graphic input device. This consists of a tablet 1 in which an X-coordinate sensor and a Y-coordinate sensor are integrally held on the same glass plate (grit glass plate), a holding glass plate, and a printed circuit board, and a cursor 2 with a position indicating coil.
Or a stylus pen 3 with similar functions and an A/D
It consists of a converter, a display, and a controller 4 with a power supply circuit connected thereto.

This graphical human-powered device operates by generating an electromotive force in the loop coils constituting each of the sensors by electromagnetic induction, and detecting the cursor position from the phase difference cup of the electromotive force. That is, a loop-shaped position indicating coil 5 is provided in the carnol 2 or the stylus pen 3 as shown in FIG. 2, and a sine wave current is applied to the coil 5. An electromotive force e is generated across the sensor 6 in a direction perpendicular to the sensor 6 as shown in FIG.

By inducing this sensor 6, position data corresponding to the level can be obtained. This electromotive force a0 changes in proportion to the amount of magnetic flux interlinking with the sensor 6.

Figure 4 shows the state in which they intersect. Note that X%-XI,
-X2 indicates the displacement position of the center O of the coil 5.

According to this, the electromotive force e is maximum at the center of the sensor 6, gradually decreases as it moves away from the center, and as it moves further away, the phase reverses, and eventually becomes line symmetrical about the center of the sensor 6. However, since the electromotive force C0 is symmetrical in the position of the coil 5 on the sensor 6 and the 75i, it is impossible to distinguish between the left and right positions with the sensor 6 as the center. location cannot be detected.

For this purpose, as shown in FIG. 5, two sets of sensors 5a*5b are prepared which are shifted by 1/□ of the loop width, and the coil 5 is moved across them.

Then, electromotive forces e1 and e2 as shown in FIG. 6 are generated in each sensor 5a and $b. Both electromotive forces e1te2
will have different waveforms. Therefore, by processing these two signals, each electromotive force e1. X where e2 is maximum
The position of the coil 5 between X2 and X3 can be detected.゛Next, the method for processing the signal will be explained.

Figure '7 shows the signal processing circuit, in which two electromotive forces e1e2
inputs one electromotive force e2 into the adder 8 together with the voltage e2 phase-shifted by +90 degrees by the phase shifter 7, and inputs the added output together with the reference signal eref to the phase difference detector 9 to obtain a predetermined phase difference output. get. This phase difference output is ultimately a function of the coil position, and it determines the position of the coil 5.

FIG. 8 shows the signal states of each part of the circuit, and the solid line a, the dashed line b1, and the broken line C indicate that the center 0 of the coil 5 is x2 in FIG.
It shows the change in electromotive force over time when Xml and X3 are respectively present. In this way, the electromotive force e, +, e2'1
, the addition output is the reference signal er8. Between X2 and X3, as shown in FIG.
This indicates a phase change, which allows the position of the coil 5 to be correctly identified.

Although the method described so far can obtain position information in a narrow range, in order to obtain position information in a wider range, a set of two sensors 6a and 6b shown in FIG. 5 can be used in large numbers. A set of sensors is prepared, each set is successively and repeatedly installed, one set of sensors is identified, and the previous i
By applying signal processing, it is possible to accurately obtain specific position information over a wide range.
', FIG. 10 is a block circuit diagram showing one embodiment thereof. In the same figure, 11a and 11b are s1>
This is a sensor in which a plurality of sets of sensors 6a and '6b shown in 1 are successively and repeatedly installed, and analog multiplexers 12 and 13 are connected to these.

Each of these analog multiplexers 12.13 selects a particular set of sensors 11a, 11b and outputs an electromotive force e1. e2 is outputted and input to the analog signal processing circuit 14, and the phase of the electromotive force e2 is shifted by 90 degrees to obtain the signal 02', and the phase is compared with the reference signal eref from the reference signal generator 15 to generate the signal ex. obtain.

This signal ex is input to a phase difference-to-digital converter 16 together with the output of a level determination circuit 18 that determines the output levels of the multiplexers 12 and 13. The digitally converted signal is sent to the coil 5 as lower data.
The output signal of each multiplexer 12, 13 becomes the position data as upper data. 17 is an up/down counter controlled by the output of the converter 16.

゛ To explain this circuit according to the flowchart of FIG. 11, first, the up/down counter 17 is in an up control state in the initial state.

Now, when a command is given to start operation, the up/down counter 17 enters up control, and an electromotive force is induced in one set of sensors 11a and 1lb among the consecutive sensors 1'1a and 11b due to the proximity of the coil 5. Both of these electromotive forces 81*e2 are input to the signal level determination circuit 18' and their levels are detected, and if the levels exceed a certain value, the electromotive forces e1 and e2 are added to the 90 degree phase shifted signal e2. A phase difference-to-digital conversion operation is performed on the output and the reference signal eref, and up/down stop is controlled depending on whether the output is overflow, upflow, or within the sensor, and the counter output is used to control multiplexer i2. i3 is sequentially switched and finally stops under coil A to output position data and complete position detection.

In this way, according to the above implementation method, the position of the cursor on the tablet is moved so that the cobble within the cursor approaches the sensor consisting of a loop coil, and the position of the coil corresponding to the sensor is electrically calculated and output. can do. By installing twisted sensors in the X-axis and Y-axis directions of the tablet, the cursor position on the secondary surface can be accurately detected as a coordinate output.

As explained above, according to the present invention, there is provided a cursor having a coil, a tablet having an X coordinate sensor and a Y coordinate sensor in which a loop coil is arranged to detect the coordinate position of the cursor, and a tablet output. In a graphic input device equipped with a controller and a controller for calculation, a plurality of sets are provided in which the two roof coils are shifted by half the loop width, and when the cursor approaches the coils, a signal is generated in each loop coil of a specific set. The resulting electromotive force is added with one phase shifted by 90 degrees, and the phase difference is detected by comparing the phase of the added output with the reference signal in a comparator, and the detected output is converted into position data on the sensor. This allows you to accurately specify the coordinate position on the tablet. Thus, the device can be put to practical use as a cursor drive electromagnetic induction graphic input device.

[Brief explanation of the drawing]

Figure 1 is an actual connection diagram of the electromagnetic induction graphic input device, Figure 2 is an explanatory diagram showing the positional relationship between the loop coil and the cursor side coil that compose the sensor, and Figure 3 is the root coil of Figure 2. Electromotive force level diagram. Figure 4 is a diagram explaining the state in which the magnetic flux of the cursor side coil interlinks with the loop coil. Figure 5 is a diagram explaining the arrangement of a set of two loop coils. Figure 6 is a diagram explaining the arrangement of a set of two loop coils. Figure 7 is a diagram of the electromotive force level of the 15 Loog coil induced by the cursor side coil. Figure 7 is a signal processing circuit diagram for position detection. Figure 8
The figure is a signal diagram of each part of the circuit, Figure 9 is a phase shift difference vs. cursor side coil position conversion characteristic diagram, Figure 10 is a more specific position detection signal processing circuit diagram, and Figure 11 is the circuit operation. It is a flowchart. 1...Tablet 2...Cursor-4...Controller section 5.='il L6at5b...Sensor loop Koinohi 7...Phase shifter 8...
Adder 9...Phase difference comparators 11a, 11b...Sensor loop coil 12.13
...Analog multiplexer 14...Signal processing circuit (adder and phase comparator) 16...Phase difference-position converter patent applicant Oscon Electronics Co., Ltd. Figure 8□ 0 ----b m -C

Claims (1)

[Claims] It consists of a cursor with a coil to which a constant current is supplied, and a roots coil that detects the coordinate position of this cursor. It is equipped with a tablet on which a sensor is arranged and a controller section that calculates the output of the tablet, and a plurality of sets of the two /u-pu coils shifted by half the roof width are arranged in parallel, and the cursor The signals induced in the two loop coils of a specific loop due to the proximity of the coils are added by an adder with one phase shifted by 90 degrees, and the phase of the added output is compared with the reference signal by a phase comparator. An electromagnetic induction type cursor drive type graphic input device configured to output phase difference output as position data on a sensor using a data converter.