Switchable Pixel Circuit for Low Power Wearable Displays

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Solution Overview

Problem

Wearable electronic devices face challenges in reducing power consumption due to limited battery capacity, necessitating the development of low power-consuming display screens and pixel circuits that can maintain display output with minimal energy usage.

Innovation Solution

A pixel circuit design incorporating a liquid crystal capacitor, memory circuit, driving circuit, mode-switching circuit, and control circuit, which allows for selective operation modes to reduce power consumption by storing status signals and adjusting voltage levels, thereby minimizing the time needed to drive the liquid crystal capacitor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If continuous data voltage is applied to drive the liquid crystal capacitor, then the display can maintain output, but the power consumption increases

Engineering Contradiction:

Improvepower consumptionVSAvoiddisplay output maintenance

Core Design Contradiction:

Use of energy by moving objectVSDuration of action of moving object

Solution Approach 1:

The memory circuit stores the status signal in advance, allowing the pixel circuit to switch to a low-power mode where continuous data voltage application is unnecessary. The stored status signal enables the display to maintain output without requiring continuous driving signals.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The pixel circuit uses its own stored status signal to maintain display output, eliminating the need for continuous external data voltage input. The circuit serves itself by utilizing the memorized state to sustain the display function in low-power mode.

Inventive Principle:

Principle #25Self-service

2Use of energy by moving object

If the pixel circuit operates in low-power mode with switched-off driving circuit, then power consumption is reduced, but the ability to update display content is limited

Engineering Contradiction:

Improvepower consumptionVSAvoiddisplay content update capability

Core Design Contradiction:

Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The pixel circuit dynamically switches between normal mode and low-power mode based on whether content update is needed. The mode-switching circuit allows the driving circuit to be selectively turned on or off, providing adaptive operation that balances power consumption with display update requirements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The memory circuit stores the status signal that reflects whether the display content needs updating. This feedback mechanism enables the pixel circuit to automatically determine when to switch to low-power mode and when to return to normal operation for content updates.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11282468B2Switchable pixel circuit and driving method thereof

Publication Date: 2022.03.22 AU OPTRONICS CORP

AI summary

A pixel circuit includes a liquid crystal capacitor, a memory circuit, a driving circuit, a mode-switching circuit, and a control circuit. The memory circuit is configured to store a status signal. The driving circuit includes a first terminal configured to receive a data voltage and a second terminal electrically coupled to a first terminal of the liquid crystal capacitor, and the driving circuit is configured to be ON or OFF according to a scan signal selectively. The mode-switching circuit is configured to be ON or OFF according to a mode-switching signal selectively. The control signal is electrically coupled to the mode-switching circuit at a first node, and is configured to control the voltage level of the first node corresponding to the status signal, and output a display voltage to the liquid crystal capacitor via the mode-switching circuit when the mode-switching circuit is ON.