Optical Ice Level Sensing With Heated Sensors in Refrigerators

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Solution Overview

Problem

Existing ice detection systems in refrigerators fail to accurately determine if the ice container is full due to mechanical components freezing, leading to continuous ice supply and overflow issues.

Innovation Solution

An ice detecting apparatus using infrared light transmission and reception modules, with a sensor heater to prevent frost and moisture buildup, allowing for accurate detection of the ice-full state by determining the level of ice in the container.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mechanical full ice detection lever is used to detect ice container fullness, then the detection mechanism is simple and reliable, but the lever becomes frozen in cold environments causing detection failure and ice overflow

Engineering Contradiction:
Improvedetection reliabilityVSAvoidfrost formation on sensor
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical full ice detection lever with an optical detection system consisting of a light emitting element and a light receiving element. This substitution eliminates the mechanical components that were susceptible to freezing, allowing reliable operation in cold environments without the harmful effect of frost formation on moving parts.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary heating element that applies heat to the optical detection components. This heating element acts as a mediator to prevent frost and moisture buildup on the light emitting and receiving elements, ensuring they remain functional in cold environments without directly exposing the detection system to harmful freezing conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If optical elements are used for ice detection, then mechanical freezing issues are avoided, but moisture and ice buildup on the optic elements impairs detection accuracy

Engineering Contradiction:
Improvedetection reliabilityVSAvoidlight detection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The heating element serves as an intermediary that protects the optical elements from moisture and ice buildup. By applying controlled heat to the light emitting and receiving elements, the system prevents condensation and frost formation that would otherwise impair light transmission and detection accuracy, maintaining both reliability and measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the temperature parameter of the optical elements by applying heat through the heating element. This parameter change prevents the optical surfaces from reaching temperatures where moisture condensation and ice formation occur, thereby maintaining clear light paths and accurate detection without compromising the cold environment requirements for ice storage.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the ice detection system operates continuously in a cold freezer environment, then ice can be detected accurately, but frost and moisture accumulate on the sensor causing detection errors

Engineering Contradiction:
Improveice level detection accuracyVSAvoidmoisture condensation on sensor
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The heating element acts as a protective intermediary between the cold freezer environment and the optical detection elements. It creates a localized warm zone around the sensors that prevents moisture from the cold environment from condensing on the optical surfaces, thereby maintaining detection accuracy without requiring the entire system to operate at elevated temperatures.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The heating element performs preliminary protective action by continuously or periodically heating the optical elements before moisture and frost can accumulate to problematic levels. This preventive heating maintains the optical surfaces above the dew point, preventing condensation and ice formation that would otherwise degrade detection precision over time.

Inventive Principle:
Principle #10Preliminary action

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 apparatus effectively prevents erroneous operations by ensuring the ice detecting sensor can accurately detect when the ice container is full, thereby preventing ice overflow and ensuring efficient ice supply.

Implementation Method 1

a light emitting element, and a light receiving element for receiving the light signal emitted by the light emitting element

Methodology Applied
Scientific EffectInfrared light emission and detection: Infrared Radiation

Implementation Method 2

a sensor heater for applying heat to prevent formation or removal of frost that may form on the ice detecting sensor

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2304346B1Refrigerator and ice maker thereof
Publication Date: 2018.08.22 LG ELECTRONICS INC
  • EP2304346B1 patent drawingFigure 1
  • EP2304346B1 patent drawingFigure 2
  • EP2304346B1 patent drawingFigure 3

AI summary

An ice detecting apparatus for a refrigerator the apparatus includes an ice maker, an ice container to collect ice made by the ice maker, and an ice detecting sensor to detect an amount of ice stored in the ice container. The ice detecting sensor has a transmitter module provided on one side of the ice maker and a receiver module provided on another side of the ice maker. The transmitter module is separated by a prescribed distance from the receiver module. At least one of the transmitter module or receiver module includes at least one optical element and at least one heater, and the heater is made of an electroconductive heating material.