JPS59135581A - Position detecting tablet - Google Patents

Abstract

PURPOSE:To detect the position where the pressure is applied on a pressure-sensitive sheet by providing the sheet consisting of a pressure-sensitive resistor which varies its resistance value with application of pressure. CONSTITUTION:The resistance value of a pressure-sensitive sheet 11 is reduced since a rubber piece 32 to which the external pressure is applied has the elastic deformation and therefore metallic particles 31 attached on the surface of each piece 32 are adhered close to each other. Then the pressure is applied onto the sheet 11 with a position designating pen 16 via a protecting film 15 and a resistance film 13, and a conduction film 12 and the film 13 conduct at the pressure applied point. Under such conditions, a changeover switch 17 is changed toward an electrode 14A. Then the resistance value between the film 12 and the electrode 14A is first detected by a detector 18. The positions designated by the pen 16 are distributed on a curved line on the sheet 11, and a specific curved line on which the designated position exists can be decided by detecting the resistance value. Then the switch 17 is changed toward an electrode 14B, and the resistance value. Then the switch 17 is changed toward an electrode 14B, and the resistance value between the film 12 and the electrode 14B is detected by the detector 18. Thus the position designated by the pen 16 can be decided in the same way.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a position detection tablet board for detecting the position on a sheet where pressure is applied.

Conventionally, tablet panels have been used to detect the position indicated by a position specifying pen on a sheet and input characters, figures, etc. into an information input device according to the trajectory of the pen, using electromagnetic, electrostatic, ultrasonic, or light methods. A variety of methods are known, including methods for using this method.

However, all of these methods require special positioning pens, and it is also necessary to connect signal lines to input and output signals to these pens, so the signal lines are This has the disadvantage that it gets in the way during designated operations and has poor operability.

SUMMARY OF THE INVENTION An object of the present invention is to provide a position detection tablet board that is easy to operate and allows a simple ballpoint pen or the like to be used instead of a special pen that requires a signal line as a position specifying means.

The present invention provides a pressure-sensitive sheet made of a pressure-sensitive resistor whose resistance value changes when pressure is applied; a conductive film disposed on both sides of the pressure-sensitive sheet, one of which is a resistive film; It is characterized by comprising an electrode arranged around the resistive film.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention. Reference numeral 11 is a pressure-sensitive sheet, and conductive films are disposed on both sides of the pressure-sensitive sheet 11. As shown in FIG. That is, in this example, the conductive film 12 is arranged on one side of the pressure sensitive sheet 11, and the resistive film 13 is arranged on the other side. Reference numerals 14A and 14B designate band-shaped electrodes arranged on two adjacent sides of the upper peripheral portion of the resistive film 13, 15 a protective film, and 16 a position specifying pen.

Further, 18 is connected to the electrodes 14A and 1 through the changeover switch 17.
4B and the resistance value between the conductive film 12, in other words, the electrode 14A,
A resistance value detector detects the resistance value of the resistive film 13 between 14B and the point on the pressure sensitive sheet 11 where pressure is applied, and 19 is a position designating pen on the pressure sensitive sheet 11 based on the output of this detector 18. 16 is a resistance value-position converter that determines the position of the point to which pressure is applied (hereinafter referred to as a designated position); 20 is a controller that controls the changeover switch 17 and the converter 19;

Here, the pressure-sensitive sheet 11 is formed by stacking a large number of silicone rubber pieces 32, which are elastic insulator pieces with metal particles 31 attached to the surface, and forming the whole into a sheet shape, as shown in FIG. 2(a), for example. It is something.

In the pressure-sensitive sheet 11 formed in this way, when pressure is applied from the outside, the rubber pieces 32 are elastically deformed as shown in FIG. 2(b), and the metal particles 31 attached to each surface of the sheet are in close contact with each other. As a result, the resistance value, especially the resistance value in the thickness direction, which is the direction of pressure application, decreases. Figure 3 shows an example of the characteristics of the pressure-sensitive sheet 11. In a normal state where no pressure is applied, it exhibits a high resistance of several thousand Ω, but when pressure is applied, the resistance changes depending on the pressure value. Several ohms to several tens of ohms
The resistance value decreases to a point where it becomes almost conductive.

Therefore, when pressure is applied to the pressure sensitive sheet 11 via the protective film 15 and the resistive film 13 with the position specifying pen 16 as shown in FIG. I will do it. In this state, the changeover switch 17 is switched to the electrode 14A side, and the resistance value between the conductive film 12 and the electrode 14A is first detected by the detector 18. This resistance value corresponds to the resistance value of the resistive film 13 between the position specified by the positioning pen 16 and the electrode 14A, and the position specified by the positioning pen 16 where the resistance values are equal is the position on the pressure sensitive sheet 11. distributed on a certain curve. Therefore, by detecting this resistance value, it can be determined on which curve the position specified by the position specifying pen 16 is located.

Next, the changeover switch 17 is switched to the electrode 14B side, and the resistance value between the conductive film 12 and the electrode 14B is similarly detected by the detector 18.
However, since the positions specified by the position specifying pen 16 where this resistance value becomes equal are distributed on a curve different from the above on the pressure sensitive sheet 11, the position specified by the position specifying pen 16 is similarly detected from this resistance value. We can see which curve the is on.

The converter 19 determines two curves corresponding to the resistance values detected by the detector 18, determines the intersection of these curves, that is, the position designated by the position designation pen 16, and generates a position detection output. Note that the controller 20 sends a signal indicating whether the selector switch 17 is switched to the electrode 14A or 14B to the converter 19.
Then, it is determined whether the resistance value detected by the detector 18 is between the conductive film 12 and the electrode 14A or between the conductive film 12 and the electrode 148.

FIG. 4 shows another embodiment of the present invention, in which the conductive film 12
Instead of detecting the resistance value itself between the electrodes on the resistive film 13 and the resistive film 13, the position is detected by detecting the potential change on the conductive i12 based on the resistance value, and the same part as in FIG. The same reference numeral - is attached to the explanation.

In FIG. 4, the electrode on the resistive film 13 is 14A.

They are provided at portions corresponding to four sides as shown by 14s, 14G, and 14D. Then, the opposite electrode 14A- of the electrodes 14A to 14D is supplied from the DC power supply 22 via the double-throw switch 21.
A potential difference is selectively applied between 14C and 14B-14D. In this way, on the conductive film 12, the positions specified by the position specifying pen 16 and the electrodes 14A, 14. Two types of potentials appear corresponding to the ratio of the resistance value between the designated position and the electrode 148.14D, respectively.

In each of these cases, the position specified by the position specifying pen 1 at which the potential on the conductive film 12 becomes equal is the pressure-sensitive sheet 1.
1 on different curves. Therefore, the potential detector 23
The potential on the conductive film 12 in each case is detected, and the potential-position converter 24 detects the position specifying pen 1 from this detection output.
By determining on which two curves the designated position indicated by 6 is located, the designated position can be determined in the same manner as described above.

Note that the controller 25 controls the double-throw switch 21, and this switch 21 is connected to the electrodes 14A and 14C.
The operation is to send a signal to the detectors 24 and 29 indicating whether the switch has been made to the 14B or 14D side.

The shape of the electrodes 14A to 14D is not necessarily band-shaped;
For example, as shown in FIG. 5, the shape may be a semicircle or the like.

As explained above, according to the position detecting tablet board of the present invention, the position specifying pen can be anything that simply applies pressure, so a pencil, a ballpoint pen, or a simple thin stick can be used. Since there is no need to use a cable or connect a signal line, operation is extremely simple.

Furthermore, the entire tablet board can be covered with an insulating protective film as explained in the previous embodiment, making it resistant to flakes and moisture, increasing reliability, and increasing durability against contact with the positioning pen. do.

Furthermore, in the tablet board of the present invention, position detection can be performed by detecting the resistance value of the resistive film between the electrode placed around the resistive film and the point on the pressure sensitive sheet where pressure is applied. Therefore, 7 fine striped electrodes are placed on the sheet.
1. Compared to the electrode arrangement method, it is easier to manufacture, and the resolution of position detection is not limited by the electrode arrangement pitch, making it possible to perform high-resolution position detection. There are advantages.

[Brief explanation of drawings]

FIG. 1(a>(b) is a block diagram of the entire position detection device using a tablet board according to an embodiment of the present invention and a sectional view of the tablet board, and FIGS. 2(a) and (b) are A cross-sectional view showing the pressure-sensitive sheet used in normal conditions and when pressure is applied. FIG. 3 is a characteristic diagram showing the relationship between the applied pressure and the resistance value of the pressure-sensitive sheet. FIG. 4 is another embodiment of the present invention. A configuration diagram of the position detection device and a sectional view of the tablet panel according to the present invention, and FIG. 5 are plan views showing other examples of electrode shapes in the tablet panel of the present invention. Conductive film, 13...
Resistive film, 14A to 14D... Electrode, 15... Protective film. Applicant's representative Patent attorney Takehiko Suzue Figure 1 (a) Figure 2 (a) (b) 3rd Penalty

Claims (1)

[Claims] A pressure-sensitive sheet made of a pressure-sensitive resistor whose resistance value changes when pressure is applied, a conductive film arranged on both sides of the pressure-sensitive sheet and one of which is a resistive film, and the periphery of the resistive film. A tablet board for position detection, characterized in that it is equipped with an electrode placed at the top of the board.