Capacitive Touch Slider Layout for Uniform Microwave Oven Backlighting

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Microwave ovens with conventional rotary controls face challenges in operability and achieving favorable backlight characteristics due to circuit boards and electrodes blocking light, and the use of transparent electrodes is expensive, increasing production costs.

Innovation Solution

A touch slider unit with a contact part and a light-transmitting part surrounding it, an electrode on the back surface for detecting user contact, and a light source on the back side to emit light, which is guided through a light guide plate for uniform backlighting, reducing production costs and improving operability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional rotary control or touch slider with circuit board and electrode layer is used, then the control function is achieved, but the backlight characteristic deteriorates because the circuit board and electrode layer block light

Engineering Contradiction:

Improvecontrol functionVSAvoidbacklight characteristic

Core Design Contradiction:

Ease of operationVSIllumination intensity

Solution Approach 1:

The touch slider is divided into a contact part (with electrode on back surface) and a light-transmitting part (surrounding the contact part). This segmentation allows the light-transmitting part to pass backlight while the contact part maintains touch detection functionality, resolving the contradiction between control function and backlight characteristic.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The electrode is moved from the front surface to the back surface of the contact part. This dimensional change allows the electrode to be positioned where it does not block the backlight path, while still maintaining its electrostatic capacity detection function for touch control.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Illumination intensity

If a transparent electrode is used to improve backlight characteristic, then the light transmission is improved, but the production cost increases

Engineering Contradiction:

Improvebacklight characteristicVSAvoidproduction cost

Core Design Contradiction:

Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent uses a conventional electrode material instead of expensive transparent electrode material. By positioning the electrode on the back surface and creating a separate light-transmitting part, the invention achieves good backlight characteristic using cost-effective conventional materials, avoiding the need for expensive transparent electrodes.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Ease of operation

If the electrode is disposed on the front surface of the touch slider, then the touch detection function is achieved, but the light transmission is blocked

Engineering Contradiction:

Improvetouch detection functionVSAvoidlight transmission

Core Design Contradiction:

Ease of operationVSIllumination intensity

Solution Approach 1:

Instead of placing the electrode on the front surface where it would block light, the electrode is inverted to the back surface of the contact part. This inversion allows the electrode to maintain its touch detection function while being positioned where it does not interfere with light transmission through the light-transmitting part.

Inventive Principle:

Principle #13The other way round (Inversion)

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 touch slider unit achieves a favorable backlight characteristic and improved operability while reducing production costs by using a cost-effective design that allows light to pass through the light-transmitting part and provides stable performance against foreign noise.

Implementation Method 1

a controller which detects a change in electrostatic capacity of the electrode to detect a contact of the user with the touch slider

Methodology Applied

Scientific EffectElectrostatic capacity: Capacitance

Implementation Method 2

a light-transmitting part disposed to surround a circumference of the contact part... a light source disposed on the back side of the touch slider to emit a light

Methodology Applied

Scientific EffectLight transmission: Light

Data Source

PatentUS9655172B2Touch slider unit and microwave oven having touch slider unit

Publication Date: 2017.05.16 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A touch slider unit includes: a touch slider having a contact part to be in contact with a user and a light-transmitting part disposed to surround a circumference of the contact part; an electrode disposed on a back surface of the contact part of the touch slider; a controller which detects a change in electrostatic capacity of the electrode to detect a contact of the user with the touch slider based on the detected change in the electrostatic capacity of the electrode; and a light source disposed on the back side of the touch slider to emit a light, thereby having a favorable backlight characteristic and an improved operability.