JPH0353647B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a tablet input device suitable for inputting information by detecting handwriting such as characters and figures written on an input panel according to the pressure of the writing. Regarding the input panel structure.

[Technical Background of the Invention] This type of device has a pair of planar electrodes facing each other while maintaining an electrically insulated state, and when one point on the planar electrodes is pressed, the distance between the planar electrodes is created at that position. It is a device that inputs written information by electrically detecting the coordinates of the conductive position at this time.
The following two types of input panel structures are conventionally known.

That is, in the first method, one plane electrode is formed on a fixed substrate, and the other plane electrode is formed on a sheet-like flexible substrate, and this flexible substrate is attached to the peripheral edge of the fixed substrate (the part where the plane electrode is not formed). ), and is of the so-called air gap type, in which the planar electrodes are fixed under tension to maintain constant spacing. On the other hand, the second type is a so-called pressure-sensitive sheet type in which a fixed substrate and a flexible substrate each having a planar electrode formed thereon are integrated with a pressure-sensitive conductive sheet sandwiched therebetween.

[Problems with background technology]

However, each of these conventional structures has the following drawbacks.

(i) First, with the air gap method, the sheet-like flexible substrate that serves as the writing surface is held in tension and fixed to the peripheral edge of the fixed substrate, so the position of the sheet, for example, the center of the sheet, is The tension state differs between the pen and the peripheral edge portion near the fixed position, and this causes the input sensitivity to differ even if the pen pressure is constant.

In addition, it is structurally difficult to apply a constant tension force to the flexible substrate at each peripheral edge, so the difference in tension tends to cause wrinkles or sagging in the flexible substrate. Even if the board can be fixed in place, changes in temperature and humidity will cause the board to expand and contract, changing its tension, resulting in variations in input sensitivity.

In particular, in recent years, devices with an input area of 1 m ² or more that can be used in the same way as a blackboard have begun to be developed. It is extremely difficult, and practically impossible, to install it without any tension.

(ii) On the other hand, in the pressure-sensitive sheet type, as mentioned above, the fixed substrate and the flexible substrate are fixed by sandwiching the pressure-sensitive conductive sheet.
Compared to the above-mentioned air gap method, there is no change in the position of the tensioned state of the flexible substrate, but the flexible substrate is a thin film-like sheet, and this sheet is stretched by screws or adhesive. For,
When it is stretched, wrinkles and sag still tend to occur, which causes a decrease in input sensitivity.

(iii) Furthermore, the flexible substrate needs to be replaced periodically as the durability against writing pressure and the abrasion resistance of the writing surface deteriorate. However, with the air gap method, as mentioned above, it is extremely difficult to stretch the flexible substrate under constant tension without causing wrinkles or sagging.
It is not possible to replace only the flexible circuit board. The same thing can also be said about the pressure-sensitive sheet type. For this reason, when it becomes necessary to replace the flexible printed circuit board of these conventionally structured input boards, the entire input board is replaced. However, replacing the entire input panel in this way increases maintenance costs because the replacement input panel is expensive, which is a major hindrance to practical implementation.
In particular, the price of the pressure-sensitive conductive sheet for the pressure-sensitive sheet type is high, and due to manufacturing reasons, each pressure-sensitive conductive sheet is small, about 50 cm square, so multiple sheets must be used. As a result, the input panel was extremely expensive.

[Purpose of the invention]

The present invention makes it possible to easily replace the flexible board while maintaining the input sensitivity uniformly over the entire input area, thereby eliminating the need to replace the entire input panel, resulting in low maintenance costs and a tablet input device with high input performance. The purpose is to provide an input panel structure for the device.

[Summary of the invention]

In order to achieve the above object, the present invention provides a plurality of insulating protrusions distributed in the electrode formation area of a fixed substrate or a flexible substrate, and defines the facing distance between the electrodes of each substrate by these insulating protrusions. A magnetic material or a magnet is provided on the outer periphery of the electrode forming area of the fixed substrate, and a frame-shaped fixed member provided with the magnet or magnetic material is prepared.
The flexible substrate is fixedly held on the fixed substrate by the magnetic adsorption force between the fixed member and the fixed substrate.

[Embodiments of the invention]

Figures 1a and 1b show the external appearance of a tablet input device according to an embodiment of the present invention, in which figure a is a front view and figure b is a side view. This device is in the form of a blackboard, with an input panel 1 attached to a frame 2, and this frame 2 attached to legs 3 with casters. , a frame-shaped presser plate 12 attached to its outer periphery, and an operating section 13. Note that 4 indicates a cable for transmitting input information, and 5 indicates an input pen.

On the other hand, FIG. 2 schematically shows the circuit configuration of the tablet input device in this embodiment, which has a pair of planar electrodes 11a and 11b made of resistor sheets facing each other at a constant interval. One of these plane electrodes 11a, 11b is grounded, and detection electrodes X ₁ , X ₂ ,
Y ₁ and Y ₂ are provided. Of these detection electrodes, the electrodes X ₁ , X ₂ and Y ₁ , which are opposite to each other,
Y ₂ are connected to each other, and these are selectively connected to the constant current source I ₀ by a switching circuit SW. Therefore, when an arbitrary point P of the electrode 11a, which is the writing surface, is pressed between the plane electrodes 11a and 11b with the input pen 5, each detection electrode is
Current value Ix ₁ flowing out from X ₁ , X ₂ and Y ₁ , Y ₂ ,
Ix ₂ , Iy ₁ , and Iy ₂ change. These current values are detected in each of the X and Y directions by switching the switching circuit SW, and are input as the position coordinates (x, y) of the pressing point P. In this way, the handwriting of characters and figures drawn is input into the handwriting input section 11. In addition, when erasing characters drawn on the handwriting input section 11, switch the input erasure switch SW of the operation section 13 to the erasing side, and in this state specify the area to be erased with the eraser. The information that was created will be deleted.

Now, the writing input section 11 and the presser plate 12 of the input panel 1 are constructed as follows. FIG. 3 is a side sectional view showing the configuration. In the figure, reference numeral 20 denotes a board on which a thin iron plate 21 as a magnetic material is adhered, and a fixed substrate body 30 is adhered to this board 20 with adhesive tape. This fixed board main body 30 is, for example, as shown in FIG.
Polyester film base material 31 with a thickness of 100 μm
A planar electrode is formed on the surface of the electrode. This planar electrode has a protective film 33 made of carbon formed on an aluminum layer 32. Then, the fixed substrate main body 30 covers the entire surface of this protective film 33 with a fifth
As shown in the figure, insulating protrusions 34 are arranged at equal intervals. This insulating protrusion 34 has a diameter of 700 mm.
It consists of hemispherical silicon members with a diameter of ~900 μm and a height of approximately 100 to 150 μm, and the spacing between them is 4 to 8 mm.
It is stipulated in Note that these insulating protrusions 34
is formed by silk printing. Also, 35 in the figure
indicates adhesive tape.

On the other hand, a flexible substrate 40 is arranged opposite to the fixed substrate main body 30.
This flexible substrate 40 has a thickness of 10 to 10 μm on the back side of a 100 μm thick polyester film base material 41.
A resistor layer 42 as a flat electrode made of carbon with a thickness of about 20 μm is formed, and a coating material 43 is coated on the surface.
was formed. This coating material 43 is processed so that it can be written on with a commercially available water-based pen or whiteboard pen.

By the way, a frame-shaped press plate 12 is attached to the peripheral edge of the board 20. This holding plate 12 is made by pasting a magnetic sheet on the back side of a thin vinyl chloride sheet, and is attracted to the boat 20 by the weak adsorption force generated between it and the iron plate 21 of the board 20. The flexible substrate 40 is held between the two.

Because of this structure, in order to attach the flexible substrate 40, first attach the flexible substrate 40.
is placed on the surface of the fixed board main body 30 and aligned, and then the presser plate 12 is placed so as to correspond to the peripheral edge of the board 20, that is, the position corresponding to the outer peripheral part of the fixing position of the fixed board main body 30. . Then, a magnetic adsorption force is generated between the magnetic sheet of the presser plate 12 and the iron plate 21 of the board 20, and the presser plate 12
is attracted to the board 20, and as a result, the flexible substrate 40 is held between the holding plate 12 and the board 20, and is held fixed as it is. Therefore, it is possible to extremely easily attach the flexible substrate 40 when assembling the input panel and when replacing the flexible substrate 40.

Also, at this time, since the flexible substrate 40 is supported by a large number of insulating protrusions 34 formed on the fixed substrate main body 30, it is necessary to tension the flexible substrate uniformly and with a large force as in the case of an air gap method. In addition to fixing the presser plate 12 by magnetic adsorption, the flexible substrate can be mounted with a simple operation while keeping the tension constant and with very little wrinkles or sagging.

In this embodiment, since the insulating protrusion 34 is provided to support the magnet 40, the locus near the insulating protrusion 34 will not be input when characters or figures are drawn. However, this input omission in the locus can be compensated for by signal processing, and there is no problem. Also, even if no correction is made, the insulating protrusion 3
4 is very small as mentioned above, so it does not actually pose any problem with the resolution of a normal display monitor or printer.

As described above, in this embodiment, the flexible substrate 40 is connected to the insulating protrusion 3 provided on the fixed substrate body 30.
4, and the flexible substrate 40 is fixed by the holding plate 12 to which a magnetic sheet is attached, so that the flexible substrate 40 is kept in a uniform tension state and does not cause wrinkles or sagging. It can be installed extremely easily. Therefore, there is no need to replace the entire input panel as in the past, and maintenance costs can be significantly reduced. Further, as described above, since the attachment state of the flexible substrate 40 can be maintained in a good condition, changes in input sensitivity depending on the input position can be suppressed, and as a result, high-quality information can be input.

Note that the present invention is not limited to the above embodiments. For example, in the above embodiment, the presser plate 12 can be directly attached to the board 20 by just passing the flexible substrate 40.
However, the iron plate 21
Instead, other weakly magnetic materials may be used, and if the attraction force is sufficiently large, the fixed substrate main body 30 may be held therebetween. Furthermore, the magnetic sheet may be provided on the board 20 side instead of on the holding plate side, or even on both sides. Further, the insulating protrusion does not have to be a protrusion as in the embodiment described above, but may be a protrusion or the like. Further, the fixed substrate and the flexible substrate may be made of a more flexible material, so that the insulating protrusion is buried in the substrate by the pressure of the pen. This allows for a smoother writing feel. Further, as for the structure of the electrode, in addition to the planar electrode, one in which X and Y detection lines are arranged all over the input area, or one in which one is a planar electrode and the other is a switch type may be applied. In addition, the structural materials, shapes, etc. of the fixing member, the insulating protrusion, the fixed substrate, and the flexible substrate can be modified in various ways without departing from the gist of the present invention.

〔Effect of the invention〕

As described in detail above, the present invention provides a plurality of insulating protrusions distributed in the electrode forming area of a fixed substrate or a flexible substrate, and these insulating protrusions define the mutual spacing between the planar electrodes of each substrate. A magnetic material or a magnet is provided on the outer periphery of the electrode forming area of the fixed substrate, and a frame-shaped fixing member provided with the magnet or magnetic material is prepared, and the magnetic attraction force between this fixing member and the fixed substrate is increased. The flexible substrate is fixedly held on the fixed substrate.

Therefore, according to the present invention, it is possible to easily replace the flexible board while maintaining the input sensitivity uniformly in the entire input area, thereby eliminating the need to replace the entire input panel, reducing maintenance costs, and improving the input sensitivity. It is possible to provide an input panel structure for a tablet input device with high performance.

[Brief explanation of drawings]

Figures 1a and 1b show the external appearance of a tablet input device according to an embodiment of the present invention, where a is a front view, b is a side view, and Figure 2 is a diagram showing an outline of the circuit configuration of the device. Figure 3 is an exploded side sectional view showing the structure of the input panel, Figure 4 is an enlarged side sectional view of a part of the same structure, and Figure 5 is the main body of the fixed board of the input panel shown in Figure 3. It is a top view which expanded and showed a part of. DESCRIPTION OF SYMBOLS 1...Input panel, 2...Frame body, 3...Legs, 4...Input information transmission cable, 5...Input pen, 11...Writing input section, 12...Press plate, 13...Operation section, 11a, 11
b... Planar electrode, 20... Board, 21... Steel plate, 30
...Fixed board body, 31... Base material, 32... Aluminum layer, 33... Protective film, 34... Insulating protrusion, 35... Adhesive tape, 40... Flexible substrate, 41... Base material, 42... Resistor layer, 43... Coating material .

Claims (1)

[Claims] 1 a fixed substrate with a first electrode formed on one side;
a flexible substrate having second electrodes forming a pair with the first electrodes formed on a surface opposite to the first electrode formation surface; a plurality of insulating protrusions facing each other with a fixed interval between the first electrode and the second electrode; a magnetic material or magnet provided on the outer periphery of the information input area of the fixed substrate; A tablet input device comprising: a frame-shaped fixing member that presses and fixes the outer periphery of the information input area of the flexible substrate against the fixed substrate by attraction force with the magnetic material or magnet of the fixed substrate. input panel structure.