JPH076579Y2 - Keyboard system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a keyboard system using a membrane film for a membrane keyboard.

[Conventional technology]

The membrane keyboard has a simple structure and is suitable for mass production, and is therefore widely used as an input device for low-priced devices such as personal computers and calculators.

FIG. 2 is a sectional view showing the structure of the membrane film portion of a typical membrane keyboard. Membrane films 2 and 3 such as polyester films stacked one above the other
Electrode patterns 4 and 5 are formed on the lower surface and the upper surface of the film with conductive ink, and an insulating spacer 1 is sandwiched between the membrane films 2 and 3.

The electrode patterns 4 and 5 are shown in FIGS. 3 (a) and 3 (b), for example.
As shown in FIG. 5, the intersections extend in directions orthogonal to each other, and these intersections form a matrix. In the case of FIG. 3, a matrix of 3 rows and 3 columns is used for simplicity. Electrode pattern 4,5
A hole 1a is provided in the portion of the spacer 1 corresponding to the intersection point of, and when the membrane film in this portion is pressed, the pattern formed in the membrane films 2 and 3
4,5 contacts and short-circuits, and it will be in a closed state.

In an actual keyboard, a key is arranged at the intersection of the electrode patterns 4 and 5, and the film is deformed by pressing the key portion to bring the electrode patterns 4 and 5 into contact with each other at the intersection.

Membrane film is generally CP via I / O port
Used by connecting to U. FIG. 4 is a block diagram showing the configuration of the keyboard system. Membrane keyboard 10
Is connected to the CPU 12 via the input / output port 11. The keyboard 10 and the input / output port 11 are connected by the drive line 8 and the input line 9 pulled up to + 5V, and the drive line 8 selected by the input / output port 11;
Which of the keys in the matrix is pressed is detected from the input signal of the input line 9 which changes depending on the pressed position of the membrane keyboard 10 and is input to the CPU 12.

[Problems to be solved by the invention]

By the way, there is a demand to use a membrane keyboard composed of a membrane film having the same shape and the same electrode pattern as various types of keyboards by changing only the key character display of the keyboard. This is because, in an item input keyboard or the like, a keyboard having the same key arrangement can be used to handle various types of input items by changing only the character display.

Conventionally, in a keyboard using a heat-resistant printed circuit board such as glass epoxy, while using the same printed circuit board, short wires are later attached by soldering etc. to form identification wiring, and various types of keyboards are electrically connected. It was supposed to be identifiable. In this case, the CPU connected to the keyboard identifies each keyboard by reading the presence / absence of a short line and the like.

On the other hand, in the membrane keyboard, since the membrane film itself does not have heat resistance, it is not possible to retrofit a short wire or the like by soldering or the like.

Therefore, in order to make it possible to identify individual membrane keyboards, it is necessary to create multiple types of membrane films, each of which has a separate identification pattern, in spite of using the same membrane film. There wasn't. Therefore, although the membrane keyboard is originally suitable for mass production and has excellent economical efficiency, there has been a problem that the conventional characteristics cannot be sufficiently exhibited.

The present invention solves the above-mentioned problems of the prior art by using a membrane film for a membrane keyboard that can fully demonstrate the mass productivity and the economical efficiency that the membrane keyboard originally has, and the membrane film type An object of the present invention is to provide a keyboard system that can be electrically identified.

[Means for solving problems]

The keyboard system of the present invention comprises a membrane film on which an electrode pattern for key input is arranged, a CPU for identifying key information based on information output from the membrane film, the membrane film and the C film.
A keyboard system having an input / output port connected to a PU for inputting key information from the membrane film and outputting to the CPU, wherein the membrane film has a protrusion on the outer periphery and the electrode pattern. Besides, a conductor pattern for identification is arranged along the edge of the protrusion, and the conductor pattern is connected to a power source on one side and grounded on the other side, and is closed when the protrusion is not cut off. It is characterized in that it is arranged so that a potential difference is generated depending on the difference between the closed state and the open state by being in the open state when the projecting portion is cut off.

[Action]

In the membrane film used in the present invention, the conductor pattern is in either a closed state or an open state depending on whether or not the protruding portion is cut off. Therefore, by connecting the conductor pattern to a CPU or the like, it is possible to determine which state it is in. That is, it can be used as data for identification. 1
The two protrusions provide 1-bit data depending on whether or not the data is cut off. The number of protrusions may depend on the number of keyboard types to be identified.

For example, a membrane film provided with a protruding portion and a conductor pattern for identification, and a membrane film and an insulating spacer facing the membrane film are made in advance,
Assemble the keys, etc. by selectively cutting off the protrusions according to the (display) type of the keyboard. Alternatively, selective cut-off may be performed before the opposing membrane film and insulating spacers are bonded together. Further, the protrusion and the identifying conductor pattern may be formed on both of the two membrane films to be bonded together.

By using the above-mentioned membrane film and applying a voltage so that a potential difference is generated at both ends of the conductor pattern of the membrane film, the type of the membrane film is input / output according to the difference in the potential difference caused by the state of the conductor pattern. It is electrically identified through the port.

〔Example〕

FIG. 1 shows a membrane film according to an embodiment of the present invention, which is laminated with an insulating spacer interposed. As shown in the figure, the membrane films 22 and 23 are formed with electrode patterns 24 and 25 extending in directions orthogonal to each other as in FIG. 3, and the intersections of the electrode patterns 24 and 25 (the spacers have holes Is pressed, the film is deformed and the electrode patterns 24 and 25 are in contact with each other.

The membrane film of the present invention is provided with a conductor pattern for identifying the keyboard in addition to the electrode patterns 24 and 25 for key input as described above. In this embodiment, this identifying conductor pattern is formed on both films 22 and 23. That is, the projections 26 are provided on both films 22 and 23, and the identification conductor pattern 27 extending along the edges of the projections 26 is provided. When the projecting portion 26 is cut off as indicated by reference numeral 51 in FIG. 5, the conductor pattern 27 is also cut off and is in an open circuit state. On the other hand, when the protrusion 26 is not cut off as indicated by reference numeral 52 in FIG. 5, the conductor pattern 27 maintains the closed state.

The conductor patterns 27 are connected to a common ground line 70 and individual wirings 71, 72, 73, respectively, and when the conductor pattern 27 is opened, the ground line and the wiring 71, 72 or 73 are opened. Become.

As shown in FIG. 6, the keyboard 30 formed by using the above-mentioned membrane film is connected via the input / output port 31.
When connected to the CPU 32 (the projecting portion 26 is not shown in FIG. 6, only the connection relationship of the conductor pattern 27 is shown in FIG. 6), the electrode pattern 24 of the membrane film is connected via the input line 29. The electrode pattern 25 is connected to the output port 31, and the electrode pattern 25 is connected to the input / output port 31 via the drive line 28. When the electrode patterns 24 and 25 formed on the membrane films 22 and 23 come into contact with each other, (membrane)
Input information is supplied from the keyboard 30 to the input / output port 31 via the input line 29.

On the other hand, the wirings 71, 72, 73 are connected to the power supply (+ 5V) via the pull-up resistor 33 and also connected to the input / output port 31.

The protrusion 26 is selectively cut off. Any protrusion 26
Since the wirings 71, 72, 73 are grounded through the conductor pattern 27 in the state where they are not cut off, all the potentials are "0". When any of the protrusions 26 is cut off, the conductor pattern 27 is also cut along with this, and the circuit is opened. Therefore, the wirings 71, 72, 73 connected to the conductor pattern 27 are connected to the power supply voltage of + 5V via the pull-up resistor 33, so that the potential becomes + 5V. That is, the logical value is "1". Which of the wirings 71, 72, 73 becomes the logic "1" depends on which protruding portion is cut off.
Further, if two or more protruding portions are cut off, there are two or more wirings that are logic "1". In this way, the combination of the logical states of the wirings 71, 72, 73 corresponds to a ³ -bit binary signal, and 2 ³ = 8 different identification signals having different values can be obtained. That is, if three protrusions are provided, eight different keys with different displays can be identified.

As described above, before assembling the keyboard using the membrane film of the above-described embodiment, depending on the type of the keyboard, the protrusion 26 is selectively cut off (in some cases, the projection is not cut off at all). Wire an electrical signal that identifies the keyboard when connected to 7
Can be obtained from 1,72,73.

The protrusion 26 is cut off with, for example, scissors. It may also be performed by a cutter.

The protrusion 26 is not limited to the shape as in the above embodiment, but may have the shape shown in FIG. 7, for example. In this case, the corner portions 81, 81 of the strip-shaped portion 80 respectively form the protrusions, and the broken line 82,
The conductor patterns 83, 83 can be cut by cutting off the protruding portion as indicated by 82.

[Effect of device]

As described above, according to the present invention, the membrane film is
In addition to having a protrusion on the outer periphery, a conductor pattern for identification is arranged along the edge of the protrusion in addition to the electrode pattern.The conductor pattern is connected to the power source on one side and grounded on the other side. When the protrusion is not cut off, the circuit is closed, and when the protrusion is cut off, the circuit is open, so that a potential difference is generated depending on the difference between the closed state and the open state. Therefore, the electric circuit of the membrane film can be changed by selectively cutting off the protruding portion. By using such a membrane film, the type of the membrane film can be electrically identified through the input / output port according to the difference in the potential difference caused by the difference in the closed state or the open state of the conductor pattern. Further, since the same membrane film is used in the present invention and the protruding portion may be cut off according to the application, that is, the type of keyboard, mass productivity and economic efficiency can be improved. .

[Brief description of drawings]

FIG. 1 is a schematic view showing the constitution of one embodiment of the present invention, FIG. 2 is a sectional view showing the structure of a membrane film for a membrane keyboard, and FIG. 3 is a top view showing a key input conductor pattern of the membrane film, FIG. 4 is a block diagram showing the configuration of a system in which a membrane keyboard is connected to a CPU, FIG. 5 is a top view showing a state in which the protruding portion of the embodiment of the present invention is cut off, and FIG. 6 shows the membrane film of the present invention. The block diagram which shows the structure of the membrane keyboard system provided with the keyboard formed using this, FIG. 7 is the schematic which shows the other example of a protrusion part. 22,23 …… Membrane film, 24,25 …… Electrode pattern, 26,81 …… Projection, 27,83 …… Conductor pattern, 30 ……
Membrane keyboard, 71, 72, 73 ... Wiring.

Claims (1)

[Scope of utility model registration request] 1. A membrane film on which an electrode pattern for key input is arranged, a CPU for identifying key information based on information output from the membrane film, and connected to the membrane film and the CPU, A keyboard system having an input / output port for inputting key information from the membrane film and outputting to the CPU, wherein the membrane film has a protruding portion on the outer periphery, and in addition to the electrode pattern, an identification A conductor pattern for use is arranged along the edge of the protrusion, and the conductor pattern is connected to a power source on the one hand and grounded on the other hand, and is closed when the protrusion is not cut off. When the part is cut off, the circuit opens and the potential changes depending on whether the circuit is open or closed. Keyboard system characterized in that it is arranged so arises.