Microwave Oven Reflection Angle Control for Local Heating Precision
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Solution Overview
Problem
Conventional microwave ovens have limited local heating performance, unable to achieve the required energy ratio for heating food items with different initial temperatures, leading to uneven heating due to standing waves and reflected waves.
Innovation Solution
A microwave heating device with a reflection angle control device that adjusts the reflection angle of microwaves within the heating chamber, controlling standing wave distribution to improve local heating performance by directing energy more effectively to specific areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an antenna with high microwave radiation directivity is used to achieve local heating, then heating precision is improved, but energy concentration ratio is limited to about 2:1 which is insufficient for food items requiring higher energy ratios
Solution Approach 1:
The patent applies local quality by making different regions of the heating chamber have different microwave reflection characteristics. The reflection phase control device creates localized regions with controlled standing wave patterns, allowing different parts of the heating chamber to have optimized microwave energy distribution for specific heating needs.
Solution Approach 2:
The patent changes the reflection phase parameter of microwaves by using a reflection phase control device that adjusts the phase of reflected microwaves. This parameter change allows control over standing wave distribution and enables higher energy concentration ratios beyond the natural 2:1 limit of conventional directivity-based systems.
2Reliability
If microwaves are radiated into a metal-covered heating chamber, then microwave containment is improved, but standing waves are generated causing uneven heating
Solution Approach 1:
The patent uses feedback by detecting the actual standing wave distribution in the heating chamber and adjusting the reflection phase control device parameters accordingly. This feedback mechanism allows dynamic optimization of microwave distribution to maintain both containment and heating uniformity.
Solution Approach 2:
The reflection phase control device acts as an intermediary between the radiated microwaves and the food items. It controls the reflection characteristics of microwaves from the metal chamber walls, modifying the standing wave patterns to achieve more uniform heating while maintaining containment.
3Manufacturing precision
If a turntable or rotary antenna is used to prevent uneven heating, then heating uniformity is improved, but device complexity increases
Solution Approach 1:
The patent replaces mechanical systems (turntables or rotary antennas) with a stationary reflection phase control device that achieves heating uniformity through electromagnetic field control. This substitution eliminates moving parts while maintaining the ability to distribute microwave energy uniformly across food items.
4Manufacturing precision
If the antenna is directed to a specific food item for local heating, then heating precision for that item is improved, but other food items may be underheated or overheated
Solution Approach 1:
The patent segments the heating chamber into multiple zones with different reflection phase characteristics using the reflection phase control device. Each zone can be independently optimized for specific food items, allowing simultaneous precise heating of multiple items with different thermal requirements without interference between them.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The controlled standing wave distribution allows for precise heating of food items, achieving the desired energy ratio and preventing overheating of certain areas, thus enhancing local heating performance.
Implementation Method 1
configured to radiate microwaves toward a heating target to dielectrically heat the heating target
Implementation Method 2
The heating chamber is much larger than wavelengths (about 120 mm for a microwave oven) of the microwaves, so that there are generated some standing waves in the heating chamber
Implementation Method 3
a reflection angle control device provided at least part of a wall of the heating chamber and configured to control a reflection angle of the microwave
Data Source
AI summary
There are provided heating chamber, and reflection angle control device provided on upper wall configuring at least part of walls of heating chamber and configured to control a reflection angle of a microwave to control standing wave distribution in heating chamber. Reflection angle control device controls the reflection angle of the microwave when the microwave radiated from microwave radiation device is not directly absorbed into heating target but is reflected by the wall. Standing wave distribution in heating chamber can thus be controlled to be different from ordinary distribution for improvement in local heating performance.