JPS6161132B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tablet-type coordinate input device that enables detection of coordinate positions of drawings, display screens, etc.

A resistive data tablet is one of the methods for inputting characters, graphs, and other line figures by hand, or for reading the coordinates of drawings. By pressing a voltage-applied resistive plate with a detection rod, the resistance value of the resistive plate changes, and by detecting the electrical signal, an electric signal indicating the coordinate position of the resistive plate is obtained. Therefore, when this resistance plate is placed on a drawing, etc., the position of the drawing can be detected. Furthermore, this data tablet has a wide range of applications, as by drawing line drawings such as figures on the resistor plate, the electrical signals obtained thereby can be input to a computer.

A conventional data tablet will be explained using a diagram. FIG. 1 is a block diagram illustrating an example of a conventional data tablet, in which 1 is a resistance plate, 2 is a detection rod, 3 is a detection section, A and B are electrodes, S ₁ and S ₂ are switches, and V ₁ , V ₂ are currents, and a, ab, and cd are conductive potential lines. Figure 1 a shows one-dimensional coordinate detection, and b shows 2
FIG. 2 is an explanatory diagram of a method for detecting dimensional coordinates. 1st
As shown in Figure a, if two electrodes A and B are provided at both ends of the resistor plate 1 and a power supply V ₁ is connected between them, then
A potential distribution shown by conductive potential line a is obtained. Detection part 3
When the top of the resistance plate 1 is pressed with the detection rod 2 connected to the resistor plate 1, the coordinate signal of the pressed position is detected by the detection unit 3. However, with this method
Only one-dimensional coordinate signals in the axial direction can be obtained. A method shown in FIG. 1b is known as one way to solve this problem. In FIG. 1b, small electrodes A and B and C and D are provided on each opposing side of the resistor plate 1, and a power supply _V1 is connected between the electrodes A and B via a switch _S1 , and an electrode C, A power supply _V2 is connected between D and D via a switch _S2 . When switch S ₁ is turned on, equipotential line ab is formed on resistance plate 1,
Similarly, when the switch _S2 is turned on, an equipotential line cd is formed. Therefore, when the resistor plate is pressed with the conductive detection rod 2 while the switches S ₁ and S ₂ are turned on alternately, a detection signal is obtained in the detection section 3.
You can know the coordinates of the pressed position. The x-coordinate signal of the touched position is obtained from the equipotential line ab, and the y-coordinate signal is obtained from the equipotential line cd. However, since the equipotential line is a curved line as shown in FIG. 1b, it is necessary to prepare a conversion table and correct it.

As is clear from the above, in the conventional method,
In order to obtain a two-dimensional coordinate signal, as shown in Figure 1 a and b, in order to obtain a position detection signal,
This method requires the detection rod 2 connected to the detection section 3, and has the disadvantage of low operability.

An object of the present invention is to provide an input device that makes it possible to detect two-dimensional coordinates on a resistor plate by pressing the resistor plate with a finger or a rod-shaped object.

The present invention has two resistance plates, and electrodes (A and B) are provided on two sides of the first resistance plate facing each other in the horizontal electrodes (C and D) are provided on each of the two sides, the first and second resistance plates are stacked on top of each other with an insulating spacer interposed therebetween, two power supplies and two detection units are provided, and the When connecting a power source between the electrodes of one of the first and second resistance plates, a detection section is connected between the electrodes of the other resistance plate, and the above connections are alternately switched for connection. , is a coordinate input device characterized in that, by pressing the top of one of the two resistance plates, the two-dimensional coordinates of the pressed position are detected.
Note that the two resistance plates are flexible, or at least one of them is flexible, and the insulating spacer is also flexible and becomes conductive only when pressurized. Use substances. An example of this insulating spacer is a pressure-sensitive conductive rubber sheet. In addition, instead of an insulating spacer, a frame-shaped insulating spacer with a hollow part is inserted between two resistance plates, and this hollow part is filled with a transparent fluid (liquid or gas) having low viscosity electrical insulation properties. Tablets can also be used. The two resistance plates are arranged so that the directions of electric fields generated when a power source is connected to the electrodes of each resistance plate are orthogonal to each other. The two power supplies and the two detection units are connected to the two resistance plates as follows. First, as a first cycle, between the electrodes of the first resistance plate (for example, A, B
A first power source is connected between the electrodes of the second resistor plate (for example, between CDs), and a second detection unit is connected between the electrodes of the second resistor plate (for example, between CDs). A first detection unit is connected between the electrodes (A, B), and a second power source is connected between the electrodes (C, D) of the second resistance plate, and the first cycle and the second Switching connections are made so as to alternately produce cycles of . The switching connection can be easily realized by electronic circuitry.

In the above-described configuration and connection state, when one of the two resistance plates is pressed with a finger or a rod-shaped object, the two-dimensional coordinates (x,
y) is detected by the two detection units. Note that as the power source, either direct current or alternating current can be used. The above-described coordinate input device according to the present invention does not require a detection rod connected to the detection section, and can be performed using a finger or a simple rod-shaped device.
It has the feature that all you have to do is press the resistance plate. The second feature is that since the equipotential lines generated on the two resistance plates are straight lines, there is no need for correction using a conversion table as in the conventional case of FIG. 1b. Furthermore, as a third feature, since the tablet according to the present invention is flexible, it can be placed on a gently curved surface such as a cathode ray tube and detect the coordinates of the position of the curved surface.

Hereinafter, the present invention will be explained with reference to the drawings. FIG. 2 is an explanatory diagram of one embodiment of the present invention, FIG.
4 and 5 are detection parts, 6 is an insulating spacer, A, B,
C and D are electrodes, S ₃ , S ₄ , S ₅ and S ₆ are changeover switches,
V ₁ and V ₂ are power supplies, x and y are coordinate signals, and A and B are contacts. In FIG. 2a, the changeover switch S ₃ ,
If S ₄ , S ₅ , and S ₆ are connected to the contact RO side, a power supply is connected between electrodes A and B of resistor plate 1, as shown in Figure 2b.
V ₁ is connected, and a detection section 5 is connected between electrodes C and D of the resistance plate 1'. Therefore, in this case, the resistor plate 1 is a voltage-driven resistor plate, and the resistor plate 1' is an electrode plate, so that the detection section 5 can detect the coordinates of the position in the X-axis direction. Next, if switches S ₃ , S ₄ , S ₅ , and S ₆ in FIG.
A detection section 4 is connected between electrodes B, and a power source _V2 is connected between electrodes C and D of the resistive plate 1'. In this case, the resistance plate 1 becomes an electrode plate and the resistance plate 1' becomes a voltage-driven resistance plate, so that the detecting section 4 can detect the coordinates of the position in the Y-axis direction. Switch S ₃
The function of alternately switching _S6 to contacts A and B can be easily realized using a known electronic circuit.
By alternately switching the switches S ₃ to _{S 6} and pressing the top of one of the resistance plates 1 and 1' with a finger or a rod-shaped object in the state shown in FIG. 2 b and c,
The detector 5 receives a coordinate signal x, and the detector 4 receives a coordinate signal y. Note that the insulating spacer 6 in FIG. 2a is an example of a pressure-sensitive conductive rubber sheet, and this pressure-sensitive conductive rubber sheet has a resistance value that increases when pressure is applied.
It has characteristics that change by as much as 10 ⁶ , and the part that is pressurized becomes conductive. Therefore, the resistance plates 1 and 1' are electrically connected at the position where pressure is applied with the finger. Instead of this pressure-sensitive conductive rubber sheet, a frame having a wide hollow portion may be inserted between the resistance plates 1 and 1', and this hollow portion may be filled with a low-viscosity liquid or gas.

Hereinafter, the principle of detection operation will be explained using diagrams. FIG. 3 is a circuit diagram of _{the connection} shown in FIG.
R ₃ , R ₄ and R ₅ are resistances, V ₁ is a power supply, p and p' are conduction points, x is a coordinate signal, and b is a contact point. In FIG. 3, when the point p of the resistor plate 1 is pressurized, the insulating spacer becomes conductive as described above, and the points p and p' are electrically connected. At this time, the resistance value of the resistance plate 1 is formed as shown by resistance R ₁ and resistance R ₂ . Further, the resistor plate 1' is also formed of a resistor _R3 and a resistor _R4 . The detection unit 5 is formed of a voltage follower using an operational amplifier, and the resistance value of the resistor _R5 is set to an extremely large value (R5≫R1) by the resistance values of the resistors ( _R1 + _R2 ) and ( _R3 + _{R4 ) .} +R ₂ , R ₃ +R ₄ ), the input impedance of the detection unit 5 becomes high impedance, so the potential at point p on the resistor plate 1 is detected and the coordinate signal x is obtained. Since the coordinates are detected by the same operation in the connection shown in FIG. 2c, the explanation will be omitted.

As described above, the present invention does not require a detection rod (such as a stylus) used to press a position on the tablet as in conventional tablets, and has the feature that a finger or a rod-shaped object can be used, and the operability is improved. improves. Further, the tablet is a tablet in which one or both of the resistance plates 1 and 1' is flexible. Therefore, the tablet according to the invention is also capable of detecting the coordinate position of a gently curved surface, for example the surface of a cathode ray tube.

An application example of the present invention will be explained with reference to the drawings. FIG. 4 is a sectional view illustrating an example of application of the present invention,
1 and 1' are resistance plates, 6 is an insulating spacer, 7 is an indicator rod, and 8 is a cathode ray tube. As shown in FIG. 4, place the resistance plate on the display surface of the cathode ray tube 8, and
By pressing the upper part with the pointing rod 7, the coordinates of the pressed position can be detected. It goes without saying that the detection rod 7 can be replaced with a finger. As is clear from the foregoing, the tablet according to the present invention is flexible and has the characteristic of being able to detect the coordinates of a position on a curved surface.

As described above, the present invention uses two resistance plates to obtain a linear equipotential distribution and enables two-dimensional coordinate detection, and eliminates the need for correction processing using a conversion table as in the past. It also has the feature that it does not require a detection rod connected to a detection section like the conventional one, and can be replaced with a finger or the like.

[Brief explanation of the drawing]

FIG. 1 is a block diagram explaining a conventional data tablet, FIG. 2 is a block diagram explaining an embodiment of the present invention, FIG. 3 is a circuit diagram of an embodiment of the present invention, and FIG. 4 is a block diagram of the present invention. It is a sectional view explaining one application example of the invention, and the symbols used in the figure are as follows. 1, 1': Resistance plate, 2: Detection rod, 3, 4, 5:
Detection unit, 6: Insulating spacer, 7: Indicator rod, 8: Braun tube, A, B, C, D: Electrode, R ₁ , R ₂ ,
R ₃ , R ₄ , R ₅ : Resistance, S ₁ , S ₂ , S ₃ , S ₄ , S ₅ , S ₆ :
Switch, V ₁ , V ₂ : Power supply, a, ab, cd: Equipotential line, p, p': Continuity point, x, y: Coordinate signal, i,
B: Contact point.

Claims (1)

[Claims] 1. In a coordinate input device using a resistive data tablet, a first
a second resistance plate provided with a pair of electrodes on opposing sides so as to generate an equipotential line distribution orthogonal to the equipotential line distribution generated by the electrodes provided on the first resistance plate; an insulating spacer inserted between the first resistance plate and the second resistance plate, a first power supply and a first detection unit connected to the pair of electrodes of the first resistance plate, and the second resistance plate. a second power source and a second detection section connected to a pair of electrodes of the resistance plate; a first power source connected to the first resistance plate and a second detection section connected to the second resistance plate; and a second connecting means that connects a first detection section to the first resistance plate and a second power source to the second resistance plate, A first resistive plate, an insulating spacer, and a second resistive plate are stacked in close contact with each other, and the first resistive plate and the second resistive plate are connected by the first connecting means and the second connecting means. The two-dimensional coordinates of the pressed position are detected by alternately supplying power to the first resistor plate and the second resistor plate, and pressing the top of either the first resistor plate or the second resistor plate. Coordinate input device. 2. The coordinate input device according to claim 1, wherein at least one of the first resistance plate and the second resistance plate has flexibility. 3 A patent in which, instead of the insulating spacer, a frame-shaped spacer is inserted to create a hollow part between the first resistance plate and the second resistance plate, and the hollow part is filled with a transparent insulating fluid. A coordinate input device according to claim 1.