Reflective LCD Circuit for Low-Power Contactless Charging

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Solution Overview

Problem

Existing portable electronic devices require physical contacts for power supply, which are prone to failure and leakage, and consume excessive power when using contactless charge by electromagnetic induction.

Innovation Solution

Incorporating a reflective liquid crystal display with transistors using oxide semiconductors, a rechargeable battery capable of contactless charging, and a nonvolatile semiconductor memory device with low power consumption, eliminating the need for physical contacts and optimizing power usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If contactless charge by electromagnetic induction is used, then physical contacts are eliminated, but power consumption increases

Engineering Contradiction:

Improvecontact reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the liquid crystal display adaptive to power conditions - it can operate in different modes (full color, grayscale, or reflective) depending on the available power from contactless charging, allowing the system to dynamically adjust its power consumption characteristics

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the display system by using oxide semiconductor transistors with extremely low off-state current, enabling the display to maintain operation at very low power levels that are compatible with contactless electromagnetic induction charging

Inventive Principle:

Principle #35Parameter changes

2Reliability

If physical contacts are used for power supply, then power supply is reliable, but contact failure and leakage occur

Engineering Contradiction:

Improvepower supply reliabilityVSAvoidcontact failure and leakage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical contact-based power supply system with a contactless electromagnetic induction charging system, eliminating all mechanical contact components that are prone to failure, wear, and leakage while maintaining reliable power transfer through magnetic field coupling

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If contactless charge by electromagnetic induction is used, then physical contacts are eliminated, but power supply stability deteriorates

Engineering Contradiction:

Improvecontactless operationVSAvoidpower supply stability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent implements self-service through the rechargeable battery that automatically manages power storage and supply, stabilizing the power output from electromagnetic induction charging without requiring external regulation, and through the oxide semiconductor transistor that inherently maintains stable electrical characteristics

Inventive Principle:

Principle #25Self-service

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

Enables reliable operation without physical contacts and reduces power consumption, even when power supplied through contactless charge is low.

Implementation Method 1

capable of charge by contactless charge

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a transistor including an oxide semiconductor... the off-state current per unit channel width of a transistor is lower than or equal to 100 aA/μm

Methodology Applied

Scientific EffectSemiconductor conduction control: Conduction (electrical)

Implementation Method 3

reflective liquid crystal display

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS12416943B2Electronic device including a circuit storing a signal

Publication Date: 2025.09.16 SEMICON ENERGY LAB CO LTD

AI summary

A portable electronic device that can operate even when electric power supplied through contactless charge by electromagnetic induction is low is provided. The portable electronic device includes a reflective liquid crystal display which includes a transistor including an oxide semiconductor, a power source portion which includes a rechargeable battery capable of charge by contactless charge, and a signal processing portion which includes a nonvolatile semiconductor memory device. In the portable electronic device, electric power stored in the rechargeable battery is used in the reflective liquid crystal display and the signal processing portion.