JPH0673254B2 - Key input device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a key input device such as a membrane.

2. Description of the Related Art In recent years, devices having a control circuit including a microcomputer are provided with an operation unit having a keyboard 6 for input as shown in FIG. 2 in order to convey the intention of the outside, especially the operator. There is. In the conventional key input method, FIG. 8 (a)
As shown in, the mainstream is a matrix circuit composed of a microcomputer output signal system and an input signal system. There are minute switches and a membrane structure as a constituent part of the switch part of the key matrix type keyboard.

A key input method using an analog / digital conversion input (hereinafter referred to as A / D input) as shown in FIG. 8 (b) is also considered.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the case of the matrix method, if the operation content of the device becomes complicated, the number of keys on the keyboard increases accordingly, and even if the matrix method is used, the number of input / output terminals must be increased. , The input / output terminals of the contents that should be controlled are insufficient. In addition, the number of signal cables between the keyboard and the control device will increase, and the cost will increase due to the connectors and wires. It is generally considered that the maximum limit is 24 keys with 6 outputs x 4 inputs.

Also, in the case of A / D input method, it is necessary to increase the resolution of A / D input and the number of its terminals when processing a large number of keys. There are many problems in terms of cost and practicability. Also, to increase the number of A / D input terminals for keys,
Since it is necessary for inputting sensors, etc., it is thought that the maximum is about two.

The present invention solves the above-mentioned conventional drawbacks, and an object of the present invention is to provide an effective key reading method in place of the A / D input method for the key matrix method in the key input method of the operation unit.

Means for Solving the Problems In order to achieve the above object, the key input method of the present invention utilizes a general input terminal and an A / D input terminal of a microcomputer, and the above-mentioned 2 is provided on a membrane type keyboard having good operability. Insert a contact sheet and a spacer sheet connected to the terminals of the type, and configure a conductive sheet and a character sheet on top of it, and when a key is pressed, the conductive sheet comes into contact with the pattern sheet through the gap of the spacer and the electrical signal The configuration is such that it enters into two types of terminals and is transmitted to the microcomputer to determine the type of key.

Operation The present invention is a membrane type keyboard in appearance due to the above configuration, but the inside is not a matrix method using conventional output terminals, but a matrix with two types of input terminals, a general input terminal and an A / D input terminal. Since it is configured, the resolution of A / D input is 1 when the number of keys is increased.
By increasing the level, the number of keys increases by the number of general input terminals.With the normal number of keys, the number of input terminals can be reduced and the output terminals are not used, so the control range can be expanded by utilizing the extra output terminals. , Specifications and performance can be improved. Also, the ROM capacity of the microcomputer can be set in the same steps as in the past.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows an external view of a high-frequency heating device according to an embodiment of the present invention. Reference numeral 1 denotes a main body of the high-frequency heating device, and a heating chamber 2 is provided in the main body 1. Heating chamber 2
A stirrer and a turntable (not shown) are provided therein to make the radio wave distribution more uniform and to improve the finish of the food. Reference numeral 3 denotes an operation unit provided at the opening of the heating chamber 2 for the user to set a cooking sequence such as cooking output and time. The operation unit 4 includes a control circuit device including a microcomputer 5a. 5 and a keyboard 6 for transmitting the user's intention to the microcomputer. By the input signal / information of the microcomputer 5a given from the keyboard 3,
The microcomputer 5a executes the cooking sequence according to the programmed contents and controls it.

FIG. 3 shows a main circuit of a high frequency heating apparatus according to an embodiment of the present invention. The magnetron 7 is provided as a high frequency oscillator, and a transformer 8 for supplying electric power to the magnetron 7 and a switch 9 for opening and closing the power supply for the transformer 8 and for connecting and disconnecting the high frequency output of the magnetron 7 are provided. Further, the microcomputer 5a, normal input terminals K ₁ ~K _4, comprises an A / D input terminal A / D _1, each terminal is connected so as to correspond to each key of the keyboard 6, the microcomputer 5a A voltage (here, 5 V) that becomes the power supply of the A / D input together with the power supply is also connected to the keyboard 6. The keyboard 6 is provided with keys such as a cooking output key, a cooking time key, and a start key. Each key has an independent switch function, and each switch function is an input terminal of the microcomputer 5a. (K _{1 to} K ₄ , A / D ₁ ) is configured to open and close.

FIG. 4 shows the configuration of the switch function of the key portion of the keyboard 6. 10 is a character sheet panel that clearly shows the position of the key part and constitutes the exterior part, and is designed to be easy for the user to understand. A conductive sheet 11 wetted with a conductive material such as aluminum is formed in the lower part thereof, and a contact gap is formed in the lower part with a contact sheet 13 forming a contact of a switch function, and insulation is provided except for a key contact. There is a spacer 12 provided to secure the space, and a space portion is provided in the contact portion of the spacer 12 so that the conductive sheet 11 and the contact sheet 13 directly face each other. The contact provided on the sheet and the conductive sheet 11 are in contact with each other. Further, a reinforcing plate 14 is provided to reinforce the whole.

Further, the conductive sheet 11 is in contact with the metal part of the high-frequency heating device main body with a screw or the like, and the control device 5 is also connected to the main body with a screw or the like. Electrically, the + 5V power source of the microcomputer 5a passes through the metal part of the main body. It is connected to the conductive sheet 11 of the keyboard 6. Further, the main body of the high-frequency heating device is connected to the ground, and the conductive sheet 11 produces an effect as a measure against static electricity from the outside.

The structure of the contact sheet 13 of the keyboard 6 is shown in FIG. As shown in the figure, the contact of each key is the pattern of P ₁ and P ₂ ~.
The pattern of P ₅ is arranged in the shape of a comb, and printed pattern resistors (R ₁ , R ₂ , R ₃ ) with a large resistance value such as carbon are formed in a part of the pattern of P _1. There is.

In the case of FIG. 5, it has a 16-key contact and has a pattern P ₁ for A / D input terminals and 4 patterns for general input terminals (P ₂ , P ₃ , P ₄ ,
It is composed of P ₅ ), and the number of connection terminals to the control device 5 is 5, so that it is possible to reduce the cost from 8 in the conventional matrix method and to achieve cost merit. Also,
As described above, by inserting 3 resistors to generate the divided voltage of the A / D input, carbon printing can be adequately applied as described above, which is very reasonable in terms of cost.

Further, the present invention, the key is pressed, except when the conductive sheet 11 containing 5V is in contact with the contact sheet 13 through the spacer sheet 12, no voltage is applied to the pattern on the contact sheet, since a / D pattern P ₁ is also generally input pattern _{(P 2, P 3, P} 4, P 5) are all at the same potential, migration occurring silver material often used in the same pattern does not occur It is a structure that the quality is very good.

The operation of the above configuration will be described below.

When food is put in the heating chamber 2 and each key on the keyboard 6 of the operation unit 4 is pressed to set the cooking time and output, the conductive sheet 11 at the position of the pressed key bends,
The contacts provided on the contact sheet 13 are closed between the spacers 12. For example, if you press the Power key, the input terminal K ₁ and A /
An input signal is given to each D input terminal J ₁ . The key contact part of the contact sheet 13 is connected to + OV, and when the contact is closed, the "Hi" level (+ 5V) is input to the input terminal K ₁ from the first, and the other input terminals K ₂ , K ₃ , K ₄ is “l
o "level (OV). Next, the A / D input terminal A / D ₁ connected to the contact provided on the same key is applied with + 5V potential from the key contact to the ladder circuit. As a result, when the contact is closed, the A / D level is input, and the key (Power
Key). Now set the resolution of the laser circuit to 4 levels. The microcomputer 5a has input terminals K ₁ , K ₂ , K ₃ , K ₄ and A /
It has the program processing that makes the matrix configuration as shown in Table 1 of D input terminal A / D ₁ , and the input is given to each input terminal by the pressed key, and what key is pressed accordingly. It is determined whether the key is a key and the key is read. In this case, the key is the "Power" key as shown in FIG.

Next, a method of identifying each key will be described with reference to FIG. The A / D ₁ of the microcomputer 5a is controlled by the resistances R ₁ , R ₂ , R ₃ , and R _X shown in Fig. 1.
There are four types of A / D voltage input to the terminals.

Also, since four keys are connected to each of the four general input terminals (K ₁ , K ₂ , K ₃ , K ₄ ), the matrix table as shown in FIG. 5 can be written.

In other words, with the POWER key in the above example, input K ₁ at level 1. If it is S ₃₃ , it means that K _{3 is} input at level 3. The microcomputer 5a, first determines general input type (K ₁ ~K _4), then determining the level of the A / D input determines the type of key. In addition, POWER, S connected to the voltage of level 1
_{The 12} , S ₁₃ , and S ₁₄ keys have a preferential position in their respective columns. For example, if you enter a key POWER key and S ₂₁ at the same time, because the voltage of the A / D level 1 to ₁ terminal occurs, the higher priority ones of the level number less. Therefore, the priority key can be realized only by deciding the position of the matrix, and the ROM capacity and RAM capacity increased by the program are not necessary.

As described above, according to this embodiment, compared to the conventional key matrix method, the number of input terminals for key scanning of the microcomputer 5a can be reduced, and the A / D resolution of the A / D input can be increased to increase the keyboard. The increase in the number of keys can be easily dealt with. Further, since it is not necessary to use the output terminal of the key scan output of the microcomputer 5a, it is possible to expand the utilization and control functions of external devices such as sensors and switches.
In addition, since the output terminal of the microcomputer 5a having a margin can be secured, the degree of freedom in design is expanded in the program design of the microcomputer 5a, and as a result, the margin of the ROM capacity of the microcomputer 5a is produced.

Incidentally, FIG. 6 is an explanatory view showing the second embodiment of the present invention, and FIG. 7 is a pattern diagram thereof.

Advantages of the Invention (1) Compared to the conventional key matrix method, the number of microcomputer input terminals can be reduced and the resolution level of the A / D input terminals can be increased to easily cope with an increase in the number of keyboard keys. You can

(2) Since the key matrix is composed of the general input terminals and the A / D input terminals, the number of keys can be easily increased by increasing the number of terminals having either margin.

(3) Since the key matrix is composed of general input terminals and A / D input terminals, the accuracy of A / D does not have to be improved compared to the conventional key input composed of A / D input terminals only. A pattern resistor can be configured in the membrane, and it can be easily realized without increasing the cost.

(4) Compared with the conventional key matrix method, since the microcomputer output terminals are not used at all, these can be used to expand the control functions such as the utilization of external devices such as sensors and switches, and the expansion. It also enables detailed support.

(5) Since the number of lead-out patterns is smaller than that of the conventional key matrix method, the number of pins of the connector connecting the membrane and the P plate can be reduced.

(6) In the configuration of the present invention, since the voltage is applied only after the key is pressed, there is no potential difference when the key is not pressed, and therefore migration between patterns does not occur, so that the pattern design of the membrane is easy. .

(7) Compared with the conventional key matrix system, since the key scan output terminal of the microcomputer is not used at all, the program for the key scan can be omitted, and the margin of the ROM capacity of the microcomputer can be increased.

(8) A key with a high priority can be configured simply by arranging it, which can be realized without burdening the ROM of the program.

(9) Since the conductive sheet is entirely under the character sheet and is directly connected to the device, it is resistant to noise such as static electricity from the outside.

[Brief description of drawings]

FIG. 1 is a block diagram of a key input device according to an embodiment of the present invention, and FIG. 2 is an external view of a high-frequency heating device provided with the device.
FIG. 3 is a circuit diagram of the same high-frequency heating device, FIG. 4 is an exploded perspective view of the key portion, FIG. 5 is the same operation explanatory diagram, and FIG. 6 is an operation explanatory diagram of the second embodiment of the present invention. Figure 7 is the same pattern diagram,
FIG. 8 is a block diagram of a conventional key input device. 1 ... Main body, 4 ... Operation part, 5a ... Microcomputer, 6 ... Keyboard, 10 ... Key panel, 11 ... Conductive sheet, 12 ...
… Spacer sheet, 13 …… Contact sheet.

Claims (4)

[Claims] 1. An analog / digital conversion input terminal and a general input terminal, a control circuit device including a microcomputer having a program function, and a membrane type keyboard for sending an input signal to the microcomputer, wherein the keyboard is A character sheet that clearly indicates the position of the key portion and forms the outer appearance portion, a conductive sheet that is made of a conductive material underneath it, and a spacer sheet that has a space at the position of each key underneath. , And a contact sheet having two types of contact groups provided under each key for each key, and the first contact group for each key provided on the contact sheet has a pattern of low resistance, The second contact group is connected to the general input terminal of the computer, and the second contact group is a resistance group that generates several kinds of resistance values such as carbon printed on the same contact sheet. And the spacer sheet connected to the analog-digital conversion input of the microcomputer, a part of the conductive sheet is connected to the power source of the microcomputer, and the character sheet is pressed to provide the spacer sheet on the key portion. The key input device configured such that the conductive sheet and the contact sheet come into contact with each other through the space of 2 and power is simultaneously applied to two types of contacts on the contact sheet. 2. The key input device according to claim 1, wherein the resistance groups of several kinds of resistance values formed on the contact sheet are collected in an open space of the contact group and continuously printed. 3. The key input according to claim 1, wherein the two types of contact groups formed on the contact sheet have a structure in which no power is applied and the potentials are the same when no key is pressed. apparatus. 4. The key according to claim 1, wherein the electrically conductive sheet is connected not only to the power source of the microcomputer but also to the ground of the device in which the keyboard is used. Input device.