Sharp Kabushiki Kaisha Corporation

Hideyuki Akao

Toshimichi Taguchi

Shoji Yamamoto

Mitsuo Morihisa

Norio Muguruma

There is disclosed an electrical signal input device suitable for use in a microwave oven or other household appliance for introducing a setting into those appliances through a simple one-touch actuation. The input device is of the membrane type which includes an actuator member composed of a generally flat plate having a plurality of elongated actuator sections on a surface thereof and carrying a plurality of first electrodes disposed wholly through an opposite surface thereof and facing against the plurality of the actuator sections, a substrate disposed in conjunction with the actuator member and having a plurality of second electrodes each corresponding to one of the first electrodes. The first and second electrodes are brought into electrical contact when the corresponding one of the actuator sections is depressed and becomes bent. It is sensed as to where the first and second electrodes are in electric contact along the length of the actuator sections.

Microwave oven having a keyboard of the membrane type

A fluorescent display tube power supply device of a microwave oven provides a stable power source for the microcomputer by rectifying the output of the first secondary coil of the commercial AC power transformer, followed by rectifying a half wave of the second secondary coil of the same AC power transformer before feeding one-half cycle of the commercial AC current to the heater of the fluorescent display tube. The power supply uses a rectifying circuit for generating the double voltage for the second secondary coil, the double voltage being mixed in the direction in which it becomes lower than the stable voltage of the microcomputer, thus generating the display erase potential VP. As a result, luminance can be held constant respective display positions without causing the voltage of the display tube to vary throughout the ON-OFF operations of the heating power source, thus eventually achieving a highly satisfactory display effect.

Microwave oven display power supply

There is disclosed an electrical signal input device suitable for use in a microwave oven or other household appliance for introducing a setting into those appliances through a simple one-touch actuation. The input device is of the membrane type which includes an actuator member composed of a generally flat plate having a plurality of elongated actuator sections on a surface thereof and carrying a plurality of first electrodes disposed wholly through an opposite surface thereof and facing against the plurality of the actuator sections, a substrate disposed in conjunction with the actuator member and having a plurality of second electrodes each corresponding to one of the first electrode. The first and second electrodes are brought into electrical contact when the corresponding one of the actuator sections is depressed and becomes bent. Discrete values of electrical resistance are sensed as a function of where the first and second electrodes are in electric contact along the length of the actuator sections.

Keyboard of the membrane type

An interface circuit is disposed between an NMOS random access memory and a PMOS central processor unit in order to ensure accurate data transfer therebetween. The interface circuit includes a pull-up system for pulling up a signal transmission line to a desired voltage level. The pull-up system is energized when the data signal is transferred from the NMOS random access memory into the PMOS central processor unit. The pull-up operation is not conducted when the data signal is transferred from the PMOS central processor unit into the NMOS random access memory.

Voltage level compensating interface circuit for inter-logic circuit

A memory protection system includes an auxiliary power supply source for maintaining information stored in a random access memory when the main power supply is terminated. When the main power supply voltage level becomes lower than a preselected level, a detection unit develops a control signal for applying a disabling signal to a chip selection terminal included in the random access memory, whereby a load such as a central processor unit connected to the random access memory is electrically disconnected from the random access memory to minimize the power dissipation.

Growing community of inventors

Osaka, Japan

Hideyuki Akao