JPH0116189Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Subject of the Invention] The present invention relates to the structure of a tablet input device that converts patterns such as characters and figures into electrical signals and sends them to a data processing device, an image display device, etc.

[Prior art and its problems]

Conventionally, tablet input devices have been developed as input devices that convert patterns such as handwritten characters and figures into electrical signals, and those using pressure-sensitive conductive rubber sheets generally have the structure shown in Figure 4. It has been adopted. Its structure consists of conductors formed on insulating films on both sides of a pressure-sensitive conductive rubber sheet 3.
This structure has a first electrode group 1 and a second electrode group 2 facing each other. (See Figure 4). When a certain pressure (several tens of grams or more) is applied to the insulating layer of the first electrode group 1 with an input writing instrument (for example, a ballpoint pen or a pencil),
The pressure-sensitive conductive rubber sheet changes from an insulating state to a conductive state, and the first electrode group and the second electrode group are electrically connected at the pressed portion (see FIG. 5). The conductive part is
Using a constant current method or a constant voltage method, the position information is sent to the rear data processing device in the form of a voltage value or the like.

Generally, the electrode surfaces of the first electrode group and the second electrode group are
To prevent incorrect input due to hand movements during input operation,
It is normal to finish as smooth as possible. However, even in a tablet input device, input pushers with different areas may be used on one input surface. For example, if you use it vertically like a blackboard, and use a pencil or felt-tip pen as an input presser, and a large-area blackboard eraser as an erasing device, the conventional input device (fourth
(see figure), input cannot be made unless a stress concentration point is provided, such as by adding protrusions to a large blackboard eraser.
In conventional input devices, as the area of the presser increases, more pressing force is required, and due to the characteristics of the pressure-sensitive conductive rubber sheet, it takes a pressing force of 1 mm ² 50 g or more per unit area to change from insulation to conduction. Is required. Therefore, if the area of the area to be erased by a blackboard eraser is 30 mm in length and 40 mm in width, a force of 1200 mm ² × 50 g is required. In reality, it is possible to input with a fraction of this force due to various factors, but in any case, as the area of the input presser increases, unless a very large force is applied, the first electrode group 1 It is not electrically connected to the second electrode group 2.

[Purpose of invention]

In order to solve these drawbacks, the present invention was developed with the aim of providing a tablet input device that can easily input data with a low pressing force even if the area of the input presser becomes large. is an input tablet device characterized in that discontinuous dot-shaped conductor protrusions are uniformly provided on the conductor surface of the electrode group.

[Configuration of Example]

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

FIG. 1 is a cross-sectional view of an embodiment of the present invention, where 1 is a first electrode, 2 is a second electrode, 3 is a pressure-sensitive conductive rubber sheet, 11 is a protective sheet for the first electrode, and 12 is a second electrode. In the protective sheet, 4 is a conductor protrusion. That is, by providing the conductor surface of the first electrode group 1 of FIG. 6, which has a conventional structure, with uniformly discontinuous dot-shaped conductor protrusions 4 with a pitch equal to or longer than the length of the contact surface. Even if the area of the presser increases to a certain extent, the pressing force is applied only to the dot-shaped conductor protrusions, making it possible to input a much smaller force than with conventional planar electrode groups. The size and pitch of the dot-shaped conductor protrusions should be equal to or less than the length of the contact surface of the input writing instrument, but if the pitch is too small, a large force will be required if the area of the presser increases. Furthermore, if the length is larger than the length of the contact surface, there will be parts where accurate position information cannot be obtained in the case of a small area input presser.

(Example 1) As a result of making various prototypes, we found that for a presser with a pressing area of 2 ^mm2 , the diameter
Especially when 200μm height 50μm to 100μm and 2mm pitch is provided in dot shape on the conductor surface, it is not only easy to manufacture but also easy to input even if the pressed area is different by about 500 times. The accuracy of the obtained position information was good.

FIG. 2 is a front view of the conductor protrusion 4. FIG.

FIG. 3 shows an embodiment of the present invention, in which the first electrode 1
A conductor protrusion 4 is also provided on the second electrode 2 facing the electrode, and the effect is greater than in the case of only the first electrode. As is clear from the figure, stress concentration points are located in the first and second electrode groups, and the displacement of the pressure-sensitive conductive rubber sheet from insulation to conduction requires only a small pressing force because the contact area is small. In addition, there are occasional electrostatic disturbances due to friction of the presser, that is, the phenomenon in which the first electrode group sticks to the pressure-sensitive conductive rubber sheet, but since there is an air layer around the conductor protrusions, the phenomenon of sticking is eliminated.

[Effect of idea]

As explained above, according to the present invention, even if the area of the presser becomes larger depending on the purpose of use, compared to conventional planar electrode groups, input can be easily made with a low pressing force, and the range of application is greatly expanded. Ru.

Get accurate location information.

Highly reliable and can withstand repeated use over long periods of time.

Since this excellent effect can be achieved, it can be widely applied to various tablet input devices, and has great industrial value.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the embodiment of the present invention, Fig. 2 is a front view of the conductor protrusion 4, Fig. 3 is a sectional view of the embodiment of the invention, Fig. 4 is a perspective view of a conventional tablet input device, and Fig. 5 is a sectional view of the embodiment of the present invention. The figure is an explanatory diagram of a sensitive phenomenon caused by a pressure-sensitive conductive rubber sheet, and FIGS. 6 and 7 are cross-sectional views of a conventional tablet input device. 1: First electrode, 2: Second electrode, 3: Pressure-sensitive conductive rubber sheet, 4: Conductor protrusion, 5: Chiyoke, 6:
Blackboard eraser, 11: Protective sheet for the first electrode, 12:
Protective sheet for the second electrode, P: input writing instrument.

Claims (1)

[Scope of claim for utility model registration] (1) In a tablet input device using a pressure-sensitive conductive rubber sheet that changes from insulation to conduction as pressing force increases, the length of the contact surface of an input writing instrument is equal to or shorter than the length of the contact surface of an input writing instrument. A structure of a tablet input device characterized in that discontinuous dot-shaped conductor projections are uniformly provided on the conductor surface of the first electrode group at pitches of the following lengths. (2) In the tablet input device, discontinuous dot-shaped dots are formed on the conductor surface of the second electrode group facing the first electrode group at a pitch that is equal to or shorter than the length of the contact surface of the input writing instrument. The structure of the tablet input device according to claim 1, characterized in that the conductor protrusions are uniformly provided.