Heat cooking device

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Solution Overview

Problem

In high-frequency heat cooking devices with touchscreens, the absence of a physical START key prevents the transmission of a signal to the main control circuit, potentially leading to unsafe conditions due to incorrect or noisy input states.

Innovation Solution

A heat cooking device design that incorporates a watchdog IC to communicate and verify the start of cooking information through a communication line, ensuring the latch circuit is only activated by a logical conjunction of signals from both the microcomputer and the watchdog IC, preventing unintended heater or microwave oven activation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a touchscreen is used as input means instead of a physical START key, then the device can achieve a more modern interface and compact design, but the signal transmission path is lost and safety is compromised

Engineering Contradiction:
Improvetouchscreen interfaceVSAvoidsignal transmission safety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces a communication line as an intermediary between the touchscreen interface and the main control circuit. The touchscreen controller sends start signals through this communication line to the microcomputer, which then activates the latch circuit. This mediator preserves signal transmission capability in the touchscreen-based system while maintaining the safety function of the latch circuit.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The control system is segmented into distinct functional blocks: the touchscreen interface, the communication line, the microcomputer, and the main control circuit with latch circuit. This segmentation allows each component to perform its specific function independently, with the communication line serving as a dedicated signal transmission path that ensures reliable and safe operation.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If only a single microcomputer controls the heating means, then the control system is simpler, but the system becomes vulnerable to failures that could cause unintended activation

Engineering Contradiction:
Improvecontrol system structureVSAvoidactivation safety
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The latch circuit serves as a protective mechanism that is activated beforehand through the communication of signals between the microcomputer and the main control circuit. This latch circuit acts as a cushion against failures by ensuring that heating means can only be activated when the proper sequence of signal transmissions occurs, preventing unintended activation due to microcomputer failures or noise.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Speed

If the latch circuit is activated by a single active signal, then the response time is faster, but the safety against noise and failures is reduced

Engineering Contradiction:
Improveactivation response timeVSAvoidnoise resistance
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The communication line transmits the start signal from the touchscreen controller to the microcomputer before the latch circuit is activated. This preliminary action ensures that the activation sequence is properly initiated and verified before the heating means can be turned on, maintaining fast response time while ensuring safety against noise and failures through the structured signal transmission process.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2735802B1Heat cooking device
Publication Date: 2017.08.30 PANASONIC HOLDINGS CORP
  • EP2735802B1 patent drawingFigure 1
  • EP2735802B1 patent drawingFigure 2
  • EP2735802B1 patent drawingFigure 3

AI summary

A heat cooking device includes: heating means 1; a main control circuit 2; a microcomputer A 3; input means 6; a microcomputer B 4; and a watchdog IC 5. When cooking start data is transmitted to the microcomputer A 3 and the watchdog IC 5 by using a communication line through the microcomputer B 4, the main control circuit 2 is turned ON based on logical conjunction of an active signal output from the watchdog IC 5 AND an active signal output from the microcomputer A 3.