JPS59114690A - Coordinate input device - Google Patents

Abstract

PURPOSE:To facilitate an easy input of character with a light pen made of iron by holding two sheets obtained by forming a resistance film evenly on an insulated plate respectively by means of a separator to set the resistance film oppositely and filling a magnetic fluid under one sheet made flexible. CONSTITUTION:The resistance films 14 and 18 are formed evenly to an insulated substrate 13 and a flexible insulated substrate 17 respectively by a vapor deposition process, etc. Then both substrates are held by means of a spacer 22 with a small gap to set the resistance films oppositely to each other. Electrodes 15 and 16 are provided to the two opposite sides of the film 14, and the electrodes (not shown in the figure) are provided to the film 18 at two sides vertical to the electrodes 15 and 16. Then a magnetic fluid 25 is filled into a space formed by the substrate 17, a flat plate 23 and a separator 24. When the light pen 26 made of iron has a touch to the substrate 13, attracting force is generated between the fluid 25 and the pen 26. This sucking force attracts the substrate 17, and a spot contact is secured between the films 14 and 18. Thus the current of each electrode changes in response to the position of the spot contact. This change of current is calculated to detect the coordinates of an input point. This method is suited to the input of a handwritten character.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a computer handwritten character coordinate input device.

The configuration of the conventional example and its problems A coordinate input device detects the coordinate position of a pen in order to input handwritten characters. The detected character information is sent to a computer or the like and displayed on a display device such as a cathode ray tube (hereinafter referred to as CRT).

Conventionally, reported coordinate input devices are equipped with detection plates that detect the coordinate positions in the X-axis direction and Y-axis direction in order to know the position of the pen for handwriting input, and these are overlapped to detect the position of the pen. There is a system in which the position coordinates of the pen are known by receiving a position signal from a detection plate by the pen through inductive or capacitive coupling between the plate and the pen, or by receiving a signal from the pen by the detection plate.

1. As other coordinate input devices that have been reported in the past, there is also a system that uses a resistor plate whose resistance values are uniformly distributed. A conventional method using this resistor plate will be explained below with reference to the drawings.

FIG. 1 is a block diagram of a conventional coordinate input device using a resistance plate. 1 is the first detection plate, in which a resistive film with a uniform resistance value is attached to the bottom surface of a flexible insulating plate so that the point input with the pen 2 is deformed downward; It has electrodes 3 and 4 on two opposing sides. First detection plate 1
A resistive film with a uniformly distributed resistance value is attached to the upper surface of the insulating plate below the insulating plate, and electrodes 6, 6 are provided on two opposing sides at a different position from the first sensing plate 1. A second sensing plate 8 having insulators 7 attached at predetermined intervals on the resistive film as spacers for insulating between the sensing plate 1 and the sensing plate 1 is opposed to the second sensing plate 8 . When there is no input by the pen 2, the first detection plate 1 and the second detection plate 8 are not electrically connected due to the insulator 7, but now the pen 2 is used to detect the first detection plate 1 and the second detection plate 8. If a pressure of a predetermined level or more is input from above to an arbitrary point, the first sensing plate 1 is flexible, so it becomes electrically conductive with the second sensing plate 8 at the input point. At this time, for example, electrode 3,
If a constant voltage is applied between electrodes 4 and 4, a divided voltage will be derived at electrode 5 that is opposite to the position of the pen 2 in the X-axis direction, and conversely
, 6, a divided voltage corresponding to the position of the pen 2 in the Y-axis direction is derived at the electrode 3.
The coordinates of the input position of the pen 2 can be known. These series of operations of applying a constant voltage between the electrodes, deriving divided voltages from other electrodes, and alternately switching these two operations in the X-axis direction and the Y-axis direction are performed by the position detection circuit 9. The position detection circuit 9 also performs analog-to-digital conversion on the input divided voltage and outputs it to the arithmetic unit as position information. By performing simple calculations on the calculation device, Ben 20
The coordinates of the input position can be known, and furthermore, characters input with the pen 2 can be displayed on a display device such as a CRT.

Figure 2 shows the second coordinate input device of the conventional example shown in Figure 1.
FIG. 8 is a front sectional view of the detection plate 8 of FIG. As mentioned above, the second detection plate 8 has a structure in which a resistive film 11 with a uniformly distributed resistance value is attached to the upper surface of the insulating plate 10, and furthermore, insulators 7 are disposed at predetermined intervals on the resistive film 11. When using P/2 manually, even if you try to input from directly above the insulator 7, this insulator 7
Due to the obstruction, the first detection plate 1 and the second detection plate 8 are not electrically connected, resulting in a so-called dead point, which has the disadvantage that input characters cannot be written at that point.

Another conventional example is one in which a pressure-sensitive conductive comb sheet is used as a spacer. Pressure-sensitive conductive rubber sheets can normally be regarded as insulators, but when a certain amount of pressure is applied in the thickness direction, the resistance value in the thickness direction near the point of application of that pressure rapidly decreases, removing the pressure. It has a kind of switch-like property in that the resistance value returns to the original value again. This pressure-sensitive conductive rubber sheet is used as a spacer by sandwiching it between two sensing plates 1 and 8 instead of the conventional insulator 7 shown in FIG. Although there is no dead point in this method, the pressure-sensitive conductive rubber sheet does not exhibit perfect switching characteristics and when the pen input pressure is not sufficient, the resistance value in the thickness direction becomes an intermediate and unstable value. , the disadvantage is that it is easy to make errors in position information.

OBJECTS OF THE INVENTION It is an object of the present invention to solve such conventional problems and to provide a coordinate input device without dead points and without errors in position information.

Structure of the Invention The coordinate input device of the present invention comprises two opposing detection plates having a uniform resistive film and electrodes on two sides thereof, and a spacer provided between the two detection plates on the side. , a flat plate placed opposite to the bottom of the sensing plate, a spacer sandwiched between the sensing plate and the flat plate, and a space surrounded by the sensing plate, the flat plate, and the spacer. It is made up of a magnetic fluid.

DESCRIPTION OF EMBODIMENTS The present invention will be explained in detail by way of an embodiment using the drawings.

FIG. 3 is a configuration diagram of a coordinate input device showing an embodiment of the present invention, and FIG. 4 is a front sectional view thereof.

The first sensing plate 12 has a resistive film 14 having a uniformly distributed resistance value attached to the lower surface of the insulating plate 13, and further has electrodes 15 and 16 on two opposing sides thereof. A flexible insulating plate is provided below the first detection plate 12.

A resistive film 18 having a uniformly distributed resistance value is attached to the upper surface of the first sensing plate 17, and a second sensing plate 21 having electrodes 19°2o on two opposing sides is connected between the first sensing plate 12 and the electrodes. 90
Make them face each other in different directions. A resin gasket 22 is sandwiched between the first detection plate 12 and the second detection plate 21 to keep the first detection plate 12 and the second detection plate 21 in an insulated state.

A flat plate 23 made of a ferromagnetic iron plate is placed below the second detection plate 21 to face it. Second detection plate 21 and flat plate 23
A resin spacer 24 is sandwiched between the second
A space surrounded by the detection plate 21, the plane plate 23, and the spacer 24 is filled with a magnetic fluid 25. Magnetic fluid is a well-known fluid that is made by dispersing iron oxide particles with a diameter of about 0.01 μm in a colloidal form in a liquid, and has the property of being attracted when a magnet is brought close to it. . With the above configuration, handwritten characters are input by approaching the magnetic pen 26 from above the first detection plate 12.

FIG. 5 shows a state where the pen 26 is approached from above the embodiment of FIG. 4 and handwritten characters are being input. When a magnetic pen 26 is brought close to the upper surface of the first detection plate 12, the second detection plate 21 is flexible, and the magnetic field lines due to the pen 26 are applied to the magnetic fluid 25 near the input position of the pen 26. Plane plate 2 through
Pen 2 moves in the direction perpendicular to Pen 3, as shown in Figure 5.
The magnetic fluid 25 near the input position 6 is absorbed upward and becomes the second
The detection plate 21 is pushed up and brought into contact with the first detection plate 12 at the input position of the pen 26, making it electrically conductive. At this time, for example, if a constant voltage is applied between the electrodes 15 and 16 by the position detection circuit 27, the electrode 19 will be
A divided voltage corresponding to the position in the axial direction is derived, and conversely, if a constant voltage is applied between the electrodes 19 and 20 by the position detection circuit 27, a divided voltage corresponding to the position of the pen 26 in the Y-axis direction is generated at the electrode 15. is derived, and position information of the input coordinates of the pen 26 can be obtained. Place the trench pen 26 on the first detection plate 1
2, the magnetic fluid 25 falls under its own weight, the first sensing plate 12 and the second sensing plate 21 separate, and return to the insulated state with the string. In this way, this coordinate input device does not use conventional insulators or pressure-sensitive conductive rubber sheets as spacers between the detection plates, and can continuously detect the position of the pen 26 without dead points or input errors. . The voltage containing position information derived from the electrodes is converted into an analog signal by the position detection circuit 27.
The coordinates of the input position of the pen 26 can be determined by digitally converting the data and outputting it to a calculation device, and by performing simple calculations on the calculation device, and further displaying the characters input by the pen 26 on a display device such as a CRT. You can also do that.

Effects of the Invention As described above, the coordinate input device of the present invention uses a method to create electrical continuity between the detection plates by attracting magnetic fluid with a magnetic pen, thereby making it possible to create electrical continuity between the detection plates compared to the conventional one. It does not have the drawbacks of dead points or input errors that are associated with methods that use spacers such as insulators or pressure-sensitive conductive rubber sheets, and it also has practical advantages such as ease of operation as there is no need to apply pressing force with a pen. It is highly effective.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a conventional coordinate input device, FIG. 2 is a front sectional view of the second detection plate thereof, and FIG. 3 is an exploded perspective view of the coordinate input device showing an embodiment of the present invention. 4 and 6 are front sectional views of the same. 012...first detection plate, 21...second detection plate, 22...middle spacer, 23...mark・Flat plate, 24...Spacer,
25...Magnetic fluid, 26...Pen. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure Z Figure 2 Figure 3 Figure 2 ＼ ? 7

Claims (1)

[Claims] a first sensing plate having a resistive film uniformly distributed on the lower surface of the insulating plate and having electrodes on two opposing sides; and a flexible first sensing plate placed oppositely below the first sensing plate. a second sensing plate having a resistive film uniformly distributed on the upper surface of the insulating plate and having electrodes on two opposing sides;
a spacer provided between the sides of the detection plate and the second detection plate, a flat plate provided opposite to the lower part of the second detection plate, and a spacer provided between the second detection plate and the flat plate. A coordinate input device comprising a spacer provided on a side between the face plate and a magnetic fluid filling a space surrounded by the second sensing plate, the plane plate, and the spacer.