Dual-Layer Display Power Management for Smartphone Sleep Modes

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Solution Overview

Problem

Existing display devices, such as smartphones with communication functions, face challenges in minimizing power consumption while maintaining convenience and functionality, especially in maintaining images on touch-screen units without continuous power consumption.

Innovation Solution

The implementation of a smartphone with a power management system that includes a battery power supply unit, communication unit, touch-screen unit, event detecting unit, and mode control unit, which allows for power-saving modes like sleep modes where the touch-screen unit maintains images without power consumption, and switches between operation modes based on detected events and user interactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the touch-screen unit continuously displays images using traditional liquid crystal display technology, then the display quality and responsiveness are maintained, but the power consumption increases significantly

Engineering Contradiction:
Improvepower consumptionVSAvoiddisplay responsiveness
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The patent divides the display system into two distinct layers: a liquid crystal display layer for high-quality visual output and an electronic paper layer for power-free image maintenance. Each layer operates independently, with the liquid crystal panel handling dynamic content and the electronic paper maintaining static content without power consumption, thereby resolving the contradiction between display quality and power usage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between different display modes based on content requirements. The control unit determines whether to display content on the liquid crystal panel, electronic paper, or both layers simultaneously, optimizing power consumption by using electronic paper for static content and liquid crystal for dynamic content, thus maintaining responsiveness while reducing energy use.

Inventive Principle:
Principle #15Dynamics

2Use of energy by moving object

If the display device enters sleep mode to save power, then power consumption is reduced, but communication functionality may be compromised

Engineering Contradiction:
Improvepower consumptionVSAvoidcommunication availability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent merges the liquid crystal display and electronic paper display systems into a unified dual-display architecture. During sleep mode, the electronic paper layer maintains displayed content without power, while the liquid crystal panel can be powered down or maintained in a low-power state. This combination ensures that communication interfaces remain functional even when the main display is in sleep mode, as the electronic paper layer provides persistent visual feedback.

Inventive Principle:
Principle #5Merging (Combining)

3Use of energy by moving object

If the liquid crystal panel is turned off to minimize power consumption, then energy usage is reduced, but the displayed image disappears

Engineering Contradiction:
Improvepower consumptionVSAvoidimage persistence
Core Design Contradiction:
Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent implements a copying mechanism where the liquid crystal panel continuously updates the electronic paper layer with the current display content. When the liquid crystal panel is turned off or enters sleep mode, the electronic paper layer retains a copy of the displayed image without requiring power, thus maintaining image persistence while minimizing energy consumption.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

Before the liquid crystal panel enters sleep mode or turns off, the system performs a preliminary action of transferring the current display content to the electronic paper layer. This ensures that the image is already preserved on the electronic paper before power is reduced, eliminating any gap in image persistence and allowing the liquid crystal panel to be fully powered down.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3547089B1Display device and the display method
Publication Date: 2024.09.18 NTT DOCOMO INC
  • EP3547089B1 patent drawingFigure 1~2
  • EP3547089B1 patent drawingFigure 3
  • EP3547089B1 patent drawingFigure 4

AI summary

Power supply unit 101 supplies power to components of smartphone 1. Communication unit 102 communicates with an external device. Touch-screen unit displays an image and receives a touch operation. Control unit 106 causes smartphone 1 to operate in an operation mode. For example, control unit 106 causes smartphone 1 to operate in a first sleep mode in which power supply unit 101 supplies power to communication unit 102, and power supply unit 101 refrains from supplying power to touch-screen unit 103 while touch-screen unit 103 maintains a displayed image.