Cooking Appliance Top Plate Coating for Blue LED Visibility

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Solution Overview

Problem

Conventional top plates for cooking appliances require an insulating film for touch sensors, complicating the production process and impairing aesthetic quality, while also having difficulty transmitting light from blue LEDs due to low transmittance at short wavelengths and inadequate heat resistance.

Innovation Solution

A top plate design featuring a glass substrate with a Si or Ge light shielding layer of 50-190 nm thickness and a protective layer made from silicon nitride, silicon oxide, titanium oxide, niobium oxide, zirconium oxide, or tantalum oxide, eliminating the need for an insulating film and enhancing light visibility and heat resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a Ti film is used as a light shielding layer, then good heat resistance is achieved, but an insulating film must be provided in the touch sensor region, complicating the production process

Engineering Contradiction:
Improveheat resistanceVSAvoidproduction process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the material parameter of the light shielding layer from Ti (high conductivity) to Si or Ge (low conductivity), thereby eliminating the need for an additional insulating film in the touch sensor region while maintaining light shielding effectiveness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The Si or Ge light shielding layer serves multiple functions simultaneously: it provides light shielding, acts as an insulating layer for the touch sensor, and maintains heat resistance, eliminating the need for separate insulating film in the touch sensor region

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Illumination intensity

If a Ti film is used as a light shielding layer, then metallic luster is achieved, but the production process becomes complicated due to the need for insulating film in touch sensor regions

Engineering Contradiction:
Improvemetallic lusterVSAvoidproduction process complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent changes the material parameter from Ti to Si or Ge, which can also provide metallic luster appearance while having inherently lower electrical conductivity, thereby eliminating the need for additional insulating film

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If conventional top plates are designed, then light shielding property is maintained, but visibility of blue LED light is poor due to low transmittance at short wavelengths

Engineering Contradiction:
Improvelight shielding propertyVSAvoidblue LED light visibility
Core Design Contradiction:
Ease of manufactureVSIllumination intensity

Solution Approach 1:

The patent optimizes the thickness parameter of the Si or Ge light shielding layer to a specific range (50-190 nm, preferably 70-120 nm), which balances light shielding capability with transmittance of blue LED light wavelengths

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If the light shielding layer thickness is increased, then light shielding property is improved, but transmittance of blue LED light decreases

Engineering Contradiction:
Improvelight shielding propertyVSAvoidblue LED light transmittance
Core Design Contradiction:
Ease of manufactureVSIllumination intensity

Solution Approach 1:

The patent precisely controls the thickness parameter of the light shielding layer within the range of 50-190 nm (preferably 70-120 nm), optimizing the balance between light shielding effectiveness and blue LED light transmittance

Inventive Principle:
Principle #35Parameter changes

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 solution allows for a simplified production process, maintains aesthetic quality, and provides excellent visibility of blue LED light while offering superior heat resistance and light shielding properties.

Implementation Method 1

a light shielding layer disposed on one side of the glass substrate, having a thickness of 50 to 190 nm and made of Si or Ge

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

The protective layer 3 is provided in order to prevent the light shielding layer from being oxidized by heat application

Methodology Applied
Scientific EffectOxidation prevention: Oxidation

Implementation Method 3

excellent visibility of light for indication from a blue LED or the like disposed behind the top plate

Methodology Applied
Scientific EffectLight transmission: Light

Data Source

PatentEP2233840B1Top plate for cooking appliance
Publication Date: 2015.09.09 NIPPON ELECTRIC GLASS CO LTD
  • EP2233840B1 patent drawingFigure 1~2

AI summary

To provide a top plate for a cooking appliance which can be provided with a touch sensor part without involving the provision of an insulating film and has excellent visibility of light for indication from a blue LED or the like disposed behind the top plate, excellent light shielding property for preserving the aesthetic quality, and excellent heat resistance. A top plate 10 for a cooking appliance disposed over the cooking appliance includes: a glass substrate 1; a light shielding layer 2 disposed on one side of the glass substrate 1, having a thickness of 50 to 190 nm and made of Si or Ge; and a protective layer 3 disposed on the light shielding layer 2 and made of at least one material selected from the group consisting of silicon nitride, silicon oxide, titanium oxide, niobium oxide, zirconium oxide, and tantalum oxide.