Abstract: A cylindrical lens-prism light-line generating apparatus utilizing a slit-type aperture provides for origination, collimation and projection of a light-line which cooperates with a light localizer beam in aid of aligning an X-ray beam path preparatory to radiography.

Abstract: A method of browning food in a microwave oven. The method comprises alternating over the entire cooking cycle the application of power to a microwave generating device with the application of power to an infrared heater. The operational periods of each type of radiation device are automatically varied over the cooking cycle. The parameters of these periods are empirically predetermined for each broad category of food and retained in a nonvolatile memory. In one embodiment, the periods are adjusted to compensate for varying quantities of food and desired donenesses by relating them to a total cooking time per unit mass empirically predetermined for each food category and doneness. Alternatively, the periods are adjusted by entering the food mass into a microprocessor in the oven. The microprocessor calculates the cooking time by use of the food category, food mass and power input to the microwave generating device.

Abstract: A stationary microwave leakage detector and method for testing microwave ovens for the maximum power density of microwaves leaking through the oven's door seals. The leakage detector is composed of an array of antennae arranged in a line generally circumscribing the circumference of the door at a fixed distance therefrom. The antennae are spaced apart a predetermined maximum distance thus insuring that a given antennae will sense at least a portion of the narrowest possible beam of microwaves emitting from the periphery of the door. Furthermore, the spacing and arrangement of the array vis-a-vis the oven door insure that the minimum power density observed by an antenna is a known ratio of the maximum power density of a narrowest beam possibly incident thereon, thus providing a means to guarantee from the measured power density levels that there are no microwaves leaking from the oven under test greater than a certain maximum power density.

Abstract: A microwave oven including a microwave power source, a microprocessor controller for controlling the microwave power source in response to user entered input data relating to cooking modes, cooking time, etc., optically readable bar codes associated with respective input data, a hand held optical scanning wand extendable from the oven to be moved adjacent a bar code for reading same, and means for converting the optically read bar code to provide corresponding control signals and coupling the control signals to the microprocessor. The microwave power source is controlled in accordance with the optically read bar code relating to the respective input data. The optical scanner can read a bar code on a food package or a bar code related to a recipe to automatically enter into the controller the corresponding microwave oven cooking instructions.

Abstract: Method and apparatus for controlling the food cooking time in a microprocessor controlled microwave oven in response to the remotely sensed condition of the food being heated. The average food temperature is constantly derived during cooking, utilizing user entered data on the food category, the food's initial mass, and the measured input power to the magnetron. The average current and average peak voltage input to the magnetron are sensed and the absorbed power in the food is derived using the magnetron efficiency. A self-calibrating analog to digital converter provides the magnetron input power in digital form for a microprocessor controller. In one embodiment the microprocessor sequentially derives the average food temperature as a function of cooking time using the entered food data, stored cooking coefficients previously determined by regression analysis, and the measured magnetron input power.

Abstract: A microwave oven having a door configured to minimize the leakage of microwave energy is disclosed. The door includes a flat sheet of glass and a flexible metal screen substantially overlying the glass sheet. The glass and the metal screen are held in substantially coplanar relationship in a frame. The edges of the metal screen are deformed such that the mounting of the metal screen in the frame causes the central portion of the metal screen to bow away from the glass. When the door is closed the metal screen conforms to the oven front panel.

Abstract: A method of cooking thin meat in a microwave oven by determining the temperature of the thin meat as a function of humidity and temperature environmental conditions of a microwave oven heating cavity. The relative humidity of the oven heating cavity is continuously sampled during cooking, and signals indicative of the humidity are provided to a digital computing device having a memory such as a programmable microprocessor. The slope of the curve of humidity as a function of elapsed time is compared to the slope of a characteristic curve for thin meats stored in the microprocessor. The doneness time is calculated from the comparison of the curves and cooking is terminated when the calculated doneness time is reached.

Abstract: Apparatus for supporting electric range heating elements below a smooth cooking surface, including a lightweight wire frame formed with at least a pair of resilient wire members for capturing and resiliently maintaining a heating element between the wire members and the bottom of the cooking surface. A pair of resilient wire members each comprising an undulating wireform extends across the wire frame with at least one heating element being captured and maintained in position between the cooking surface and the pair of undulating wireform members. A plurality of clips lockingly engage the conventional range top frame with another clip end engaging the lightweight wire frame to form an assembly of the range top frame, the cooking surface and the lightweight wire frame with the heating elements captured between the wire frame and the cooking surface. In another embodiment, the wire frame extending around the perimeter of the cooking surface comprises an undulating wireform.

Abstract: A microwave oven having the control panel mounted on the door. The control panel includes a plurality of pushbutton switches for the user to push to control the speed, time, etc. for variable cooking in the microwave oven. The switches communicate to an electronic controller also mounted on the door. The controller converts user input into signals that control the various operating components of the oven, such as the magnetron. The controller is connected with these components via a flexible printed circuit cable which bridges the space between the door and the oven near or through the hinge area of the oven.

Abstract: An improved feed system for a microwave oven, including a shelf mounting a microwave energy source and a shelf extension protruding not more than half-way into the microwave cavity. The shelf extension acts as a microwave launching portion and includes a pair of adjacent cut-out sections with arcuate perimeters matching the rotational arc circumscribed by a pair of rotating stirrer blades. Alternative embodiments of the shelf extension - microwave launching portion are illustrated and described.

Abstract: An improved touch panel switching device including a thin, flexible plastic sheet foldable to locate respective switch contactors and contacts opposite each other, an insulating spacer member intermediate the switch contactors and contacts and having openings to enable contactor and contact communication, a rigid backing on one side and a thin, metal sheet on the other side of the plastic sheet, the metal sheet being relatively stiff and depressable at a switch position to enable engagement of a respective switch contactor and contact.

Abstract: A method and control system for regulating the output power of a magnetron in a microwave oven having a food heating cavity, a magnetron, and a waveguide coupling the magnetron to the heating cavity. The reflection coefficient within the waveguide is measured and a control signal is generated to switch the magnetron between first and second levels of power output when the reflection coefficient reaches a pre-determined value indicating that the food item within the oven has begun to defrost. In the preferred embodiment, the present invention incorporates digital signal processing utilizing a microprocessor to calculate the reflection coefficient and generate the control signal based upon digital signal inputs that are a function of the detected microwave energy within the waveguide.

Abstract: An air flow system for use in a wall-mount microwave oven is disclosed. A housing of the microwave oven has an interior which is divided into a cooking cavity and an electronic component compartment. A front face of the housing is comprised of a movable door and a control panel. A circuit board for holding electronic components is mounted within the electronic component compartment so that it is spaced from the control panel. An air passageway is defined in the area between the control panel and the circuit board. An air inlet is disposed adjacent an upper end of the control panel for admitting air into the electrical component compartment and an air outlet is disposed adjacent a lower end of the control panel for allowing air to exit from the electrical component compartment. A blower draws air in through the air inlet, and forces the air through the electrical component compartment, and out the air outlet. A mechanism diverts a portion of the air being drawn in through the inlet to the air passageway.

Abstract: A method for effectively browning foods in a microwave oven by controlling the humidity of the cooking environment. Humidity and temperature sensors are provided to measure the relative humidity of the environment surrounding a foodstuff to be browned as the food is cooked by microwave energy. The actual sensed conditions are compared with a predetermined optimum relative humidity. Adjustments to the relative humidity are then made by either increasing or decreasing the air exchange rate, or by increasing or decreasing the amount of heat added to the air exchanged, or both.

Abstract: A method of cooking meat in a microwave oven by determining the mean internal temperature of the meat which is indicative of the internal doneness of meat as a function of sensed and sampled time dependent humidity and temperature of the microwave oven heating cavity. The mean internal temperature of the meat is determined as a function of the initial temperature of the meat; a net heat loss due to surface evaporation; a net input of energy by the microwave power source, and a net convective heat loss.

Abstract: A method for indicating the optimum time at which to turn meat over in a microwave oven. The method detects the point where the absolute humidity remains constant and no longer increases indicating that the temperature of the meat has reached an equilibrium point. At the temperature equilibrium point, the meat is ready to be turned over.

Abstract: A microwave oven sensing system having a humidity sensor and a temperature sensor at an exit ventilation port of a microwave oven heating cavity to sense the exiting humidity and the air temperature of the microwave oven heating cavity. The humidity sensor and the temperature sensor are positioned to sense the "in-situ" environmental conditions of the microwave oven heating cavity such as adjacent to and by the exterior of the exit ventilation port of the microwave oven heating cavity. The sensors connect to a programmable controller and input the sensed "in-situ" environmental conditions of the microwave oven heating cavity to the programmable controller. "Characteristic humidity curves" for microwave cooking of different types of foods are stored as algorithms in a memory of the programmable controlled and the programmable controller controls the microwave cooking in accordance with a selected algorithm for the sensed "in-situ" environmental conditions.