JPH0441386Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a cursor for input devices such as digitizers and tablets for inputting information such as figures and characters. This is about the switch.

(Prior Art) In conventional cursor switches for input devices, each switch is electrically conductive or electrically conductive by mechanical operation.
It was used in a non-conducting state.

(Problem that the invention aims to solve) In conventional cursors, each switch is electrically conductive or non-conductive by mechanical operation, so it is difficult to make two switches conductive when pressed at the same time. Therefore, the priority of each switch must be set individually, and the number of switch signal lines in the connection cable between the cursor and the control device must be at least 1 greater than the number of switches as a common potential. There was a problem in that an additional number of cables were required, and the connection cable between the cursor and the control device became thicker, resulting in poor operability.

(Means for Solving the Problems) The present invention solves the above-mentioned conventional problems by providing a detection electrode for detecting pulses applied to the electrode wires of a tablet having a plurality of electrode wires arranged in the direction of the coordinate axes. The present invention proposes a cursor for an input device having a plurality of switches which are switched and inputted with a detection signal from the detection electrode, wherein the plurality of switches are constituted by a current addition circuit. be.

(Function) In the present invention, a plurality of switches arranged at the cursor are configured with a current addition circuit and connected to an operational amplifier, so that the pressing status of the plurality of switches can be confirmed by the voltage value converted from the current value.

(Example) The present invention will be described below with reference to the accompanying drawings. FIG. 2 shows an overall block diagram of a system using the cursor of the present invention. Tablet 1 has an X axis and a Y axis.
A plurality of electrode lines X and Y are arranged in the axial direction, and these electrode lines X and Y are connected to drivers 2 and 3 in each coordinate direction, and are sequentially connected through gates 4 controlled by a control circuit 12. A pulse is applied. A signal detected by a detection electrode 501 (see FIG. 1) capacitively coupled to each of the electrode lines X and Y of the tablet 1 is applied to one terminal 801 of the switch 8 via the amplifier 7. Furthermore, each switch SW of switch part 6
1, the current caused by the on/off of SW2, SW3, and SW4 is connected to the terminal of the operational amplifier 601 via the feedback resistor r5,
The voltage VO induced at 5 is applied to the other terminal 802 of switch 8. Switch 8 is control circuit 1
The common terminal 803 is connected to either 801 or 802 via the switching drive circuit 11 controlled by the switching drive circuit 11. Here, turn on/off each switch of the switch section 6.
To explain about turning off, in this embodiment, four switches SW1, SW2, SW3,
SW4 is connected in parallel, each switch SW1, SW
2, SW3, and SW4 are connected to resistors r1, r2, r3, and r4, each having a different resistance value, and the other end of each resistor r1, r2, r3, and r4 is connected to one terminal of the operational amplifier 601. It is connected. The other terminal of operational amplifier 601 is connected to reference voltage VR602. For example, when the switch SW1 is turned on, the current I1 flowing through the resistor r1 is transferred to the operational amplifier 601.
Since the imaginary short and input resistance of is infinite, I1=(Vcc-VR)/r1. Since this current I1 flows through the resistor r5, a voltage of VO=r5(Vcc-VR)/r1 is induced across the resistor r5. Currents I2, I3, and I4 flow to other SW2, SW3, and SW4 from the same relational expression, and resistance r5
A voltage VO is induced in Also, switch SW1
If SW4 and SW4 are turned on at the same time, the resistor
The current flowing through R5 is I1 = (Vcc - VR) / r1 and I4 =
(Vcc−VR)/r4 is added,
VO=r5(1/r1+1/r4)(Vcc-VR)
voltage will be induced. Furthermore, all switches
When SW1, SW2, SW3, and SW4 are turned on, (1/r1+1/r2+1/r3+1/
A current of r4) (Vcc-VR) will flow to r5. This means that the sum of the currents I1, I2, I3, and I4 determined by the resistors r1, r2, r3, and r4 flows through the resistor r5, and each current I1,
The ratio of I2, I3, and I4 can be set arbitrarily, for example, 1:2:4:8.
If you weight it like this, 2 ⁴ = 4 switches
Can express 16 levels of current. Furthermore, by arbitrarily setting the reference voltage VR and the feedback resistor r5, the output voltage VO can be made variable so as to be easily determined.

A signal sent from the common terminal 803 of the switch 8 is applied to a hold circuit 9, which holds the applied signal, digitizes it in an analog-to-digital converter 10, and applies it to a control circuit 12. The control circuit 12 performs arithmetic processing in accordance with the switched signals (the coordinate position signal of the tablet 1 and the potential of the switch section 6) while switching the switch 8. Since the arithmetic processing of the control circuit 12 is outside the scope of the present invention, a description thereof will be omitted.

Next, the actual operation will be explained with reference to the flowchart of FIG. The common terminal 803 of the switch 8 is connected to the terminals 801 and 80 by the control circuit 12.
It is connected to either one of 2. Here, control circuit 1
It is determined whether the signal applied to the switch 2 is a signal detected by the detection electrode 501 or a signal in which at least one of the switches SW1, SW2, SW3, and SW4 is turned on (S1). If no signal is detected here, the process moves to another process (S8), and other processes of the control circuit 12 are performed. When a signal is detected in step 1 (S1), the hold circuit 9 holds the potential of the detected signal (S2), and the analog-to-digital converter 10 digitizes it (S3).
The voltage is applied to the control circuit 12 (S4). Whether the applied signal is the coordinate signal from tablet 1 or the switch
Determine whether any of SW1, SW2, SW3, or SW4 is turned on (S5), and if it is a coordinate signal, calculate the coordinate position (S6), and if a switch is on, determine which switch is on. Check (S7) and return to step 1.

FIG. 4 shows another embodiment in which the switch section 13 is constructed of a current adding circuit other than an operational amplifier. Constant current elements 14, 15, 16,
17 are connected, and each constant current element 14, 15, 1
Switches SW1, SW2, SW3, and SW4 are connected to the other ends of 6 and 17, respectively, as in the first embodiment.
The other end of each switch SW1, SW2, SW3, SW4 is connected to an output terminal VO via one end of a grounding resistor r. In this circuit as well, constant currents I1, I2,
By weighting the ratio of I3 and I4 at 1:2:4:8, VO = (I1 + I2 + I3 +
A potential difference of I4)r occurs, and the maximum VO=16(I1). However, in this case, the load on VO must satisfy R<<Z.

The detection electrode uses a capacitive coupling method with the tablet, and the switch was explained in Section 4.
The present invention is not limited to this example,
It is possible to detect positional information using a cursor and to use five or more switches.

(Effect of the invention) Since the present invention has the above-mentioned configuration, even if the cursor switch becomes conductive, the on/off state can be determined by weighting the current of each switch, and the connection By reducing the number of signal lines in the cable, it is possible to reduce costs and improve operability.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a cursor explanatory diagram, FIG. 2 is an overall block diagram, FIG. 3 is a flowchart, and FIG. 4 is another embodiment. 1...tablet, 5...cursor, 501...
...detection electrode, 6 ... switch section, 601 ... operational amplifier, 8 ... switch, 12 ... control circuit, 1
4, 15, 16, 17...constant current element, SW1,
SW2, SW3, SW4...Switch, r1, r
2, r3, r4, r5, r...resistance.

Claims (1)

[Scope of utility model registration request] For an input device that has a detection electrode that detects a pulse applied to the electrode line of a tablet that has a plurality of electrode lines arranged in the coordinate axis direction, and a plurality of switches that switch and input the detection signal from the detection electrode. 1. A cursor for an input device, characterized in that said plurality of switches are constituted by a current adding circuit, and a weight of 2 ⁿ is given to the current flowing through each of said switches.