Abstract: A zoom lens has the capability to maintain image quality during image shifting for correcting for movement of the zoom lens. The zoom lens comprises, in order from the object side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having negative refractive power, and a fourth lens group having positive refractive power. When changing magnification, the first lens group and the fourth lens group remain stationary along the optical axis and the second lens group and the third lens group move along the optical axis. The fourth lens group comprises, in order from the object side, a front lens group and a rear lens group. The front lens group of the fourth lens group moves in a direction substantially perpendicular to the optical axis to correct for movement of the image position caused by movement of the zoom lens.

Abstract: A compact, high-performance zoom lens is disclosed. The zoom lens comprises four lens groups having positive, negative, negative, and positive refractive power, respectively. The lens groups are disposed so as to enable the zoom lens to produce an image of an object on an image plane over a range of magnifications from a wide-angle end to a telephoto end. The second and third lens groups move along the optical axis during zooming. The first lens group preferably includes, objectwise to imagewise, a negative lens element and first, second, and third positive lens elements. The zoom lens satisfies at least the following conditions:0.6<F.sub.T.sup.1/2 (f.sub.1 /f.sub.T)<1.00.7<1.beta..sub.2W .multidot.V.sup.1/21 <1.1wherein f.sub.1 is the focal length of the first lens group, F.sub.T is the F-number of the zoom lens at the telephoto end, .beta..sub.2W is the lateral magnification of the second lens group at the wide-angle end, f.sub.

Abstract: A zoom lens has a first lens unit which is fixed in position during zooming and has a positive refractive power, a second lens unit which is movable upon zooming and has a negative refractive power, a third lens unit which is fixed in position during zooming and has a positive refractive power, a fourth lens unit which is movable upon zooming and has a negative refractive power, and a fifth lens unit which is fixed in position during zooming and has a positive refractive power. Upon zooming from the wide-angle end to the telephoto end, the second lens unit is unidirectionally moved from the object side to the image side along the optical axis. The fourth lens unit is moved along the optical axis from the object side to the image side within the range from the wide-angle end to the middle position between the wide-angle and telephoto ends, and is moved along the optical axis from the image side to the object side within the range from the middle position to the telephoto end.

Abstract: A zoom lens system comprises, in an order from an object side, a first lens group with a positive refractive power; a second lens group with a negative refractive power; a third lens group with a negative refractive power; and a fourth lens group with a positive refractive power, wherein, for varying a focal length from a wide-end to a telephoto-end, the second lens group is moved from an object side to an image side along an optical axis and the third lens group is moved to reciprocate on the optical axis, the second lens group having an aspherical lens surface, and the aspherical lens surface is formed in a shape where the positive refractive power gradually increases or in a shape where the negative refractive power gradually decreases from the optical axis toward a periphery.

Abstract: A zoom lens system comprises in the following order from the object side: a first lens group of a positive refracting power; a second lens group of a negative refracting power; a third lens group; and a fourth lens group of a positive refracting power, wherein, when changing a focal length of the zoom lens system from a wide-angle end to a telephoto end, the second lens group is shifted in one direction along an optical axis of the zoom lens from the object side toward the image side, the third lens group is shifted so as to reciprocate along the optical axis, and the first lens group has a gradient index lens whose refractive index varies along the direction of the optical axis and which satisfies the following condition:-10.6<(.nu.2-.nu.1)/[(n2-n1).multidot.100]<-0.9whereinn1: a refractive index at an object-side vertex of the gradient index lens,n2: a refractive index at an image-side vertex of the gradient index lens,.nu.1: Abbe number at the object-side vertex of the gradient index lens,.nu.

Abstract: Disclosed is a mixing circuit. A still-picture signal (S) input from a still-picture signal input terminal and a motion-picture signal (M) input from a motion-picture signal input terminal are added together by a first adder, and the resultant signal is converted to (S+M)/2 by a first 1-bit right shifter, and to (S+M)/4 by a 2-bit right shifter. One of the outputs of those shifters is selected by a first multiplexer in accordance with shift signals CI2-CI0. The still-picture signal (S) and motion-picture signal (M) are also respectively converted by a second 1-bit right shifter and a third 1-bit right shifter to S/2 and M/2, one of which or "O" is selected by a second multiplexer in accordance with the shift signals CI2-CI0. The outputs of the first and second multiplexers are added together by a second adder to be input to a third multiplexer. The output of the third multiplexer is determined by the shift signals CI2-CI0, and is output from an output terminal.

Abstract: A microwave oven includes a heating chamber, a plurality of cooking utensils detachably disposed in the heating chamber selectively in accordance with the cooking contents, a plurality of heat sources heating food placed on or contained in the cooking utensil and including a magnetron, an oven heater and a grill heater, optical sensors determining the cooking utensil disposed in the heating chamber, and a microcomputer. The cooking utensils include a glass dish, thawing gridiron, pot, upper and lower top plates, one-legged top plate, and gridiron. A microwave cooking mode is selected when the determination of the optical sensors indicates that neither upper nor lower top plate is present in the heating chamber. A heater cooking mode is selected when either upper or top plate is present. When the heater cooking mode is selected on the basis of presence of the upper top plate, either an oven mode or a grill mode is selected depending upon presence or absence of the gridiron.

Abstract: A microwave oven includes a magnetron generating microwaves which are irradiated onto food for heating the same, a circuit substrate incorporating an electric circuit for driving and controlling the magnetron, circuit means for generating both an electrical alarming signal and a high-frequency electrical signal, and a sound producer producing an alarming sound regarding a heating operation when supplied with the alarming electrical signal and producing ultrasonic waves for the repelling of insects when supplied with the high-frequency electrical signal.

Abstract: A microcomputer-based control device for microwave ovens includes a timer defining an operation period of a magnetron and incorporated in the microcomputer, an encoder generating electrical pulses, the number of which is in accordance with an amount of angular displacement of an operation knob, the encoder being independent of the microcomputer, first and second semiconductor switches for starting an operation of the magnetron in response to either any one or a plurality of a pulse train generated by the encoder, the semiconductor switches being incorporated in the microcomputer, and a counter for setting, at the timer, a cooking period in accordance with the numer of pulses of the pulse train generated by the encoder.

Abstract: In a high frequency cooking apparatus including a magnetron, a fan motor, turntable motor, a plurality of relays for controlling them and a microcomputer controlling the relays, the microcomputer is provided with a relay test program. The relay test program is executed when specific two cooking menu selecting keys are simultaneously depressed. Consequently, pulses are sequentially supplied to all the relays and simultaneously, relay identification marks are sequentially displayed on a display unit. Based on the mechanical operation sound from each relay and the displayed content, an operator determines whether or not each relay is normal.

Abstract: A high-frequency heat source supplies a predetermined high-frequency heat output. An inverter circuit receives an AC input and supplies a high-frequency output to drive the high-frequency heat source. The inverter circuit includes a circuit for rectifying the AC input, and a switching element for switching a DC output from the rectification circuit. A timing circuit is coupled to the inverter circuit to detect a switching timing of the switching element to the inverter circuit. A controller outputs an ON/Off signal having a predetermined duty ratio corresponding to a heating output set value associated with the predetermined high-frequency heating output. The ON/Off signal is output at a predetermined timing in response to a detection output from the timing circuit. A drive circuit drives the switching element in the inverter circuit in response to the ON/Off signal output from the controller. A first isolation circuit electrically isolates the timing circuit from the controller.

Abstract: A high-frequency heating source supplies a predetermined high-frequency heating power. An AC input is supplied to an inverter circuit. The inverter circuit generates a high-frequency output signal for driving the high-frequency heating source. The inverter circuit comprises a rectifier circuit for rectifying the AC input, and a switching element for switching the DC output supplied from the rectifier circuit. The inverter circuit is controlled by an inverter control circuit. A processor supplies set heating-output data associated with the high-frequency heating power to the inverter control circuit. The inverter control circuit comprises a counter and an on/off signal generator. The counter is set to a on-period in accordance with the set heating-output data, and performs counting operation. The on/off signal generator generates an on/off signal in accordance with a count value of the counter.

Abstract: A high frequency heating source provides a predetermined high frequency heating output. An inverter receives an AC input and provides a high frequency output for driving the high frequency heating source. The inverter includes a rectifier for rectifying the AC input and a switching element for switching a DC output from the rectifier. The microprocessor outputs an ON/OFF signal having predetermined ON and OFF periods in accordance with a set output value associated with the high frequency heating output. A driver drives the switching element of the inverter in accordance with the ON/OFF signal output from the microprocessor.

Abstract: An inverter rectifies an AC input to produce a DC output and switches the DC output so as to selectively obtain a high-frequency output for microwave or induction heating. A microwave heating unit is coupled to the inverter, receives the high-frequency output for microwave heating, and generates a first heating power of a microwave. An induction heating unit is coupled to the inverter, receives the high-frequency output for induction heating, and generates a second heating power of electromagnetic induction. An output setting unit selectively sets an output setting value for the first or second heating power. An input detector detects a current value of the AC input to the inverter.

Abstract: A controlled circuit for generating signals for switching the switch elements of a DC to AC inverter. The circuit monitors the output waveform of the inverter and controls the firing of the switch elements in the inverter from DC to AC inverter circuit to restore it to a sinusoidal waveform in the event that it is distorted by non linear loads and to recover the voltage level within the allowable band in the event that it is disturbed by step load changes.

Abstract: In an induction heat cooking apparatus of the invention, an electromagnetic field is generated by a heating coil, and the generated electromagnetic field is supplied to a load so that the load is inductively heated. The cooking apparatus includes an exciter circuit for exciting the heating coil to generate the electromagnetic field; a temperature set circuit for providing a temperature set signal which designates a given target temperature of the load; and a temperature measure circuit for measuring the temperature of the load to generate a temperature measure signal which represents the measured temperature of the load. The cooking apparatus further includes a difference detector circuit for detecting a difference between the temperature set signal and the temperature measure signal and generating a difference signal. The exciter circuit receives the difference signal so as to control heat power for the heating coil.

Abstract: A control circuit for a microwave oven with a mechanical switch locking assembly, wherein a cooking start switch is available to turn on after closing a door and is turned off when the door is opened. The control circuit includes a relay for connecting a power source to energize a magnetron, and control means for controlling the relay. The control means enables the relay to connect the power source with the magnetron when the cooking start switch is turned on after connecting the control means with the power source. If the cooking start switch is already turned on prior to connecting the microwave oven to the power source, the operator must first open the microwave oven door, thus opening the start switch, and subsequently closing the door and closing the start switch. This safety procedure encourages the operator to insure that food products are placed in the oven, thus reducing the danger of operating the oven without a load.

Abstract: A control circuit for controlling a magnetron of a microwave oven includes a microcomputer output control means for controlling the energy output of the microwave oven, and a means for controlling the magnetron in response to a time signal and a food temperature signal. The control circuit includes a back-up circuit to de-energize the magnetron when cooking is complete in the event of a malfunction of the microcomputer.

Abstract: A pressure-sensitive recording paper comprising a support having coated thereon a layer of color former, said color former dissolved in at least one compound represented by the following formula: ##STR1## wherein n is an integer of 1 to 8, R and R' each represent a member selected from the group consisting of alkyl groups containing one to eight carbon atoms, and a hydrogen atom, p and q represent the number of alkyl groups, p+q being an integer of 1 to 3, and R and R' may be the same.