JPS6022369B2 - coordinate input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coordinate input device that detects coordinate information of a pressurized position by pressurizing a writing instrument or the like.

2. Description of the Related Art Coordinate input devices using an input board have conventionally been used as devices for detecting the coordinates of a Ben position in devices for inputting characters and figures into a computer, such as a handwritten character input device.

FIG. 1 is a block diagram showing an example of a conventional coordinate input device, in which 1 is a resistive film closely attached to an insulating slope, 2 is an AC power source, and 3, 4, 5, 6 are diode groups. The anodes of the diode group 6 and the cathodes of the diode group 6 are commonly connected and connected to one side of the AC power supply 2.

Also, a diode group 4 located opposite to diode group 3
The cathodes of the diode group 5 and the anodes of the diode group 5 located opposite the diode group 6 are also commonly connected and connected to the other side of the AC power source 2 and grounded. 7, 8, 9, 10
are terminal groups provided on the resistive film 1, terminal group 7 is connected to the cathode of diode group 3, terminal group 8 is connected to the anode of diode group 4, and terminal group 9 is connected to the cathode of diode group 5. The connected terminal group 10 is connected to the anode of the diode group 6.

11 is a pen, 12 and 13 are diodes, 14 and 15
is a terminal.

The tip of the pen 11 is connected to the cathode of the diode 12 and the anode of the diode 13 by a conductor, and the diode 1
The anode of the diode 2 is connected to the terminal 14, and the cathode of the diode 13 is connected to the terminal 15. Therefore, when one point on the resistive film 1 is pressurized by the pen 11, when the AC power supply 2 is negative, diode groups 3 and 4 are cut off, and diode group 5
and 6 become conductive.

Therefore, the negative voltage at the pressure point is transmitted to the pen 11, and a negative voltage corresponding to the pressure point is outputted to the terminal 14 through the diode 12. Conversely, when the AC power supply 2 is positive, the diode groups 5 and 6 are cut off, the diode groups 3 and 4 are conductive, and the positive voltage at the pressurizing point is transmitted to the ben 11 and applied to the terminal 15 through the diode 13. A positive voltage corresponding to the pressure point is output. Here, terminal groups 7 and 8 are installed at opposite ends of the resistive film 1 in the Y direction, and terminal groups 9 and 10 are installed at opposite ends of the resistive film 1 in the The negative voltage expressed represents the coordinate of the X axis,
The positive voltage drawn out to the terminal 15 means the Y-axis coordinate.

In this way, the coordinates of both X and Y koji are detected, but in a secondary coordinate input device, the coordinates are detected via the input pen due to electrical conduction caused by contact between the resistive film 1, which is the input panel, and the pen 11, which is the input pen. The coordinates were detected. However, in the case of the coordinate input device, since opposing electrodes in the X and Y directions are formed on the resistive film, when a voltage is applied between one group of terminals, it appears that no voltage is being applied between the groups. There was also a serious drawback in that a current wraparound phenomenon occurred, and it was difficult to obtain a surface with an ideal constant potential gradient, that is, an equipotential surface, and the accuracy of coordinate position decreased.

Another major drawback is that the use of an AC power source as a drive power source makes the peripheral circuits expensive, and as a result, the widespread use of coordinate input devices has been prevented.

In addition, in order to use a DC power source as a drive power source, it is necessary to use two resistive films separately for vertical and horizontal directions, or if a single resistive film is used, terminal groups are provided on the four sides of the resistive film, and these can be connected to a switch. It is necessary to connect and disconnect in the vertical and horizontal directions using a wire, etc., and in order to obtain a surface with a constant potential gradient, it is necessary to form a group of terminals that are closely spaced, making it difficult to make them dramatically cheaper. Met. On the other hand, a method has been proposed in which the coordinate position is detected by capacitive coupling without relying on conduction, in order to insert a form between the input panel and the input pen and record it while inputting. The peripheral circuitry needed to detect this would be expensive, making it impractical.

An object of the present invention is to eliminate these drawbacks by arranging a resistive film and a resistive terminal plate having a sufficiently smaller resistance value than the resistive film around the resistive film, and time-sharing the resistive film vertically and horizontally through the resistive terminal plate. The coordinate point of the pressurized point is detected by applying a predetermined voltage and applying pressure with a writing instrument, and detecting the potential of the pressurized point with a conductive film, and the resistor is sufficiently smaller than the resistive film. By using a low resistance terminal plate with a high resistance value, an ideal equipotential surface (a surface with a constant potential gradient) is formed on the resistive film, and the number of input/output lines to the resistive terminal plate is reduced. This will be explained in detail below.

FIG. 2 is a cross-sectional view showing the configuration of an input panel showing an embodiment of the present invention, in which 16 is an insulating film, 17 is a conductive film, 18 is a pressure-sensitive rubber, 19 is a resistive film, and 20 is sufficiently smaller than the resistive film 19. The resistor terminal board 21, which is made up of a resistor having a resistance value, is constructed like a Zettain Diamond board.

Note that the insulating film 16 and the conductive film 17 are made of a material that can be simulated. FIG. 3 is a block diagram centered on the resistive film 19 of the first embodiment, and 22 to 25 are a group of terminals provided on the resistive terminal plate 20, among which terminals 22a, 23
a is the left end terminal of the terminal groups 22, 23, and 22b, 23b are the right end terminals of the terminal groups 22, 23. (Note that the terminals of each terminal group are provided at approximately the same intervals as adjacent terminals.
) 26, 28, 30, 31 are diode groups, 27, 29
32 is a DC power supply, and 33 to 36 are constructed like switches. Also, 3
7 indicates a pressure point where the writing odor 38 is pressurized through the insulating film 16 by the writing odor 37. As shown in FIG. 3, a resistive terminal plate 20 made of a resistor having a sufficiently smaller resistance value than the resistive film 19 is arranged around the resistive film 19 and electrically connected thereto.

To explain in more detail with respect to the block diagram of FIG. 3, the terminal group 22 is connected one-to-one with the cathodes of the diode group 26 and the diode 27, respectively, and the anodes of the diode group 26 are commonly connected and connected to the common terminal of the switch 33.

The anode of the diode 27 is connected to the positive side of the DC power supply 32. The terminal group 23 is connected one-to-one to the anodes of a diode group 28 and a diode 29, respectively, the cathodes of the diode group 28 are commonly connected and connected to the common terminal of the switch 34, and the cathode of the diode 29 is connected to the negative side of the DC power supply 32. Connected and grounded. Further, the terminal group 25 and the terminal 23b are connected one to one to the cathode of the diode group 30, respectively.
The anodes of the diode group 30 are commonly connected and connected to the common terminal of the switch 35.

Furthermore, the terminals 22a and the terminal group 24 are connected one-to-one to the anodes of the diode group 31, respectively.
The cathodes of the two are commonly connected and connected to the common terminal of the switch 36. Thus, the terminal 22a has a diode group 26.
The leftmost diode and cathode of the diode group 31 and the anode of the uppermost diode of the diode group 31 are connected, and the terminal 23
b shows the anode of the rightmost diode of the diode group 28 and the cathode of the lowermost diode of the diode group 30.
, and one diode is connected to each of the other terminals. Also, switch 33
and normally closed contact terminal of switch 36 (hereinafter referred to as NC
It is called a terminal.

) is connected to the positive side of the DC power supply 32 and the two switches 33
, 36 (hereinafter referred to as NO terminals) are connected to the negative side of the DC power supply 32. Further, the NO terminal of the switch 34 and the NO terminal of the switch 35 are connected to the positive side of the DC power supply 32, and the NC of the two switches 34 and 35 is connected to the positive side of the DC power supply 32.
The terminal is connected to the negative side of DC power supply 32. Here, the case where pressure is applied to the pressure point 38 from above the insulating film 16 using the writing instrument 37 will be explained.
The conductive film 17 is electrically conductive at the pressurizing point 38.

Now, at a certain timing, switch 3 is switched to the state shown in Figure 3.
3 to 36, the terminal group 22 on the resistor terminal board 20 is connected to the potential of the DC power supply 32 (hereinafter referred to as E [V]) by the forward voltage drop of the diode (hereinafter referred to as V). [V]) is subtracted from the potential (E-v [V]).
is applied to the terminal group 23, and a potential (v [V] higher than OV by the forward voltage drop of the diode is applied to the terminal group 23. Therefore, the terminal group 22 at the upper end of the resistor terminal board 20
An E primary [V] voltage is applied between the terminal group 23 at the lower end. At this time, the diode groups 30 and 31 are reverse biased, so that the diode groups do not have any effect on the resistive film 19 and the two resistor terminal plates that cause the potential to fluctuate. What should be noted here is the terminal 22 of the resistor terminal board 20.
A and 23a and between terminals 22b and 23b also have E- [V
) is applied, and has the same potential gradient as the resistive film 19. Therefore, the left and right portions of the resistive film 19 and the resistive terminal plate 20 have the same potential gradient in the vertical direction, and no current flows between the resistive film 19 and the resistive terminal plate 20 in the left-right direction. Thus, the potential on the resistive film 19 at the application point 38 is detected by the conductive film 17, and the vertical coordinates of the input panel are detected.
Now, at the next timing, the switches 33 to 36 operate in the opposite direction, and each point changes from the solid line state to the dotted line state, so that the horizontal potential of the input board can be obtained in exactly the same way.

As explained above, in the first embodiment, by providing the resistive terminal plate 20 made of a resistor having a resistance value sufficiently lower than that of the resistive film 19 by providing the resistive terminal plate 20 around the resistive film 19, the resistive terminal plate 20 is to the external circuit (diode group 2 in the first embodiment)
6, 28, 30, 31 and diodes 27, 29) are set to a value where the resistance value of the resistor terminal plate 20 is sufficiently smaller than the resistance value of the resistive film 19.
The number of resistors is extremely small, and since terminal plates can be provided in both vertical and horizontal directions on one resistive film 19, there is an advantage that coordinates in both vertical and horizontal directions can be obtained with one resistive film 19.

Further, a resistor terminal plate 20 is used as this terminal plate, and diode groups 26, 28, 30, 31 and a diode 27 are used.
, 29 are biased in opposite directions when they are not used to apply a potential to each other, so that the potential gradient on the resistive film 19 is constant and its accuracy is very high. In other words, there is an advantage that equipotential surfaces can be realized with high precision. Next, since a DC wire is used as the drive power source, the peripheral circuitry is simple, and as explained above, only one resistive film 19 is required, and the number of connections between the resistor terminal board and the external circuit is small, making the input panel inexpensive. It also has the advantage of being able to provide

In the first embodiment, the diode groups 26, 28, 30, 31 and the diodes 27, 29 are used for switching, but the switching may be performed more directly using a switch.

FIG. 4 is a block diagram showing the second embodiment.
46 is connected to each terminal on the resistor terminal plate 20 of the switch as shown in FIG. When trying to obtain the coordinates in the vertical direction, if at a certain timing each contact of each switch 39 to 46 becomes connected as shown by a solid line, terminal group 22 has terminal 2.
Voltage E [V] is applied to terminals 2a and 22b, and terminal group 23, including terminals 23a and 23b, is connected to ○[V], and terminal group 24 and terminal group 25 are in an open state,
Both the resistive film 19 and the resistive terminal plate 20 provide a potential gradient in the vertical direction. The potential difference at this time is E [V].
When the contacts of the switches 39 to 46 are connected to the dotted lines at the next timing, the voltage E [V] is applied to the terminals 2, 2b, 23b and the terminal group 25, and the terminals 22a, 2
3a and terminal group 24 are connected to ○ [V] as shown in Fig. 22a.
, 22b and the terminal group 23 excluding terminals 23a and 23b are in an open state, and a potential gradient from right to left is obtained in both the resistive film 19 and the resistive terminal plate 20.

In this way, the vertical and horizontal coordinates of the pressure point 38 due to the writing odor 37 are obtained as potentials by the conductor film 17 via the pressure-sensitive rubber 18. Note that the present invention is not limited to the first embodiment and the second embodiment, and various applications are possible, which will be described below.

First, in the embodiment, the resistor terminal board 20 was explained as one piece for the upper, lower, left and right sides, but it does not have to be one piece, and it can be divided into four parts, top, bottom, left, and right. The ends of the terminals may be connected with conductive wires.

In addition, by doing so, manufacturing costs can be further reduced. Second, in the embodiment, the resistor terminal plate 20 is provided around the resistive film 19, but the resistor terminal plate 20
The position is not limited to the periphery of the resistive film 19, but may be provided in close contact with the end portion of the resistive film 19.

That is, by providing the resistive terminal plate 20 in close contact with the resistive film 19, electrical connection between the resistive film 19 and the resistive terminal plate 20 can be extremely easily obtained. Thirdly, in the embodiment, as shown in FIG.
Although the resistive film 19, the resistive terminal plate 20, and the insulating substrate 21 are provided in the explanation, the order is not limited to this order.If the resistive film 19 and the resistive terminal plate 20 are made of a flexible material, the resistive film 19, the resistive terminal plate 20, and the conductive film 17 may be arranged in opposite positions. Fourthly, in the embodiment, conduction was obtained at the pressurizing point 38 between the resistive film 19 and the conductor film 17 using the pressure sensitive rubber 18, but the pressure sensitive rubber 18 is not necessarily required, and an appropriate gap may be used. This will be easily understood by engineers in the field.

In particular, when the resistor terminal plate 20 is arranged on the upper four sides of the resistor film 19 as explained in the second section, if an insulating spacer is provided between the resistor terminal plate 20 and the conductor film 17, the resistor film 19 and the conductor film It is possible to create a structure in which an appropriate gap is formed between the pressure-sensitive rubber 18 and the pressure-sensitive rubber 18 is not required. Fifth, in the embodiment, the potential at the pressure point 38 on the resistive film 19 is
8 to the conductor film 17, and the potential of the pressure point 38 was obtained from the conductor film 17, but in a device that does not need to obtain a copy of input characters, the pressure sensitive rubber 18 and the conductor film 17 are not used. It is also possible to provide a connection cord to the writing smell 37 and obtain a potential directly from the tip of the writing smell.

As described in detail above, in the present invention, the resistive terminal plate 20 having a sufficiently smaller resistance value than the resistive film 19 is electrically connected and placed around the resistive film 19, so that the potential gradient on the resistive film 19 is reduced. A coordinate input device with constant and high precision can be constructed, and since the number of connection points between the external circuit and the resistor terminal plate 20 is reduced, the coordinate input device can be provided at a low cost. Therefore, it can be widely used in fields such as not only keyboards but also input panels for online character recognition.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a conventional coordinate input device.
FIG. 2 is a sectional view showing the configuration of an input panel showing an embodiment of the present invention, FIG. 3 is a block diagram of the first embodiment, and FIG. 4 is a block diagram of the second embodiment.
FIG. 2 is a block diagram of an embodiment of the invention. 1... Resistive film closely adhered to the insulating plate, 2...
... Father-flow dew source, 3 to 6 ... Diode group, 7
~10...Terminal group, 11...Ben, 1
2, 13... Diode, 14, 15...
...terminal, 16...insulating film, 17...conductor film,
18...Pressure sensitive rubber, 19...Resistive film,
20... Resistance terminal board, 21... Insulating board,
22-25...Terminal group, 22a...Left end terminal of terminal group 22, 22b...Right end terminal of terminal group 22, 23a, .・・・．・The leftmost terminal of the terminal group 23, 23b...The rightmost terminal of the terminal group 23, 26,
28, 30, 31...Diode group, 27, 29...Diode, 32...DC power supply, 33-36...
・...Switch, 37... Writing instrument, 38... Pressure point, 39-46""" switch. Fig. 1 Fig. 2 Fig. 3 Fig. 4

Claims (1)

[Claims] 1. A coordinate input device that detects coordinate information of the tip position of a pressurizing body in contact with an input panel provided with a resistive film, which is electrically connected to the resistive film and is made of a resistor having a sufficiently smaller resistance value than the resistive film. A coordinate input comprising a terminal board, means for time-divisionally applying a DC voltage to the terminal board in the vertical and horizontal directions, and a detection means for detecting the potential at a pressurized point on the resistive film. Device.