Display Unit Pixel Circuit for Power Reduction

Solution Overview

Problem

Current display units, particularly organic EL display units, face challenges in reducing power consumption due to variations in drive transistor characteristics, which affect image quality and increase power usage during voltage writing operations.

Innovation Solution

A display unit configuration that includes a unit pixel with a light-emitting device, a capacitor section comprising two capacitors coupled in series, and a first transistor that delivers a voltage to the node, allowing for preparatory driving to set a threshold voltage and subsequent write driving to set pixel voltage, enabling efficient power management by alternating drive current supply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If threshold voltage correction is performed each time pixel voltage is written, then image quality is maintained, but power consumption increases

Engineering Contradiction:

Improveimage qualityVSAvoidpower consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent performs threshold voltage correction in advance during a preparatory driving phase before the actual pixel voltage writing. By correcting the threshold voltage of drive transistors beforehand, the system ensures accurate current drive for the light-emitting devices during normal operation without needing to perform correction repeatedly, thus reducing power consumption while maintaining image quality

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements periodic threshold voltage correction by alternating between preparatory driving (which includes correction) and write driving phases. This periodic approach corrects threshold voltage variations at regular intervals rather than continuously, reducing the frequency of high-power correction operations while maintaining sufficient image quality through periodic refreshment of the correction data

Inventive Principle:

Principle #19Periodic action

2Manufacturing precision

If drive transistor characteristics are corrected frequently, then image quality deteriorates due to variations, but power consumption increases

Engineering Contradiction:

Improveimage qualityVSAvoidpower consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent performs threshold voltage correction in advance during a preparatory driving phase before the actual pixel voltage writing. By correcting the threshold voltage of drive transistors beforehand, the system ensures accurate current drive for the light-emitting devices during normal operation without needing to perform correction repeatedly, thus reducing power consumption while maintaining image quality

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent incorporates feedback mechanisms where the drive transistor characteristics are measured and used to adjust the correction values applied during preparatory driving. This feedback loop allows the system to adapt to actual transistor variations and maintain image quality while optimizing the correction frequency and intensity to minimize power consumption

Inventive Principle:

Principle #23Feedback

3Measurement precision

If data signal transmission frequency is increased, then voltage writing accuracy improves, but driving capability requirement increases

Engineering Contradiction:

Improvevoltage writing accuracyVSAvoiddriving capability

Core Design Contradiction:

Measurement precisionVSPower

Solution Approach 1:

The patent performs threshold voltage correction in advance during a preparatory driving phase before the actual pixel voltage writing. By correcting the threshold voltage of drive transistors beforehand, the system ensures accurate current drive for the light-emitting devices during normal operation without needing to perform correction repeatedly, thus reducing power consumption while maintaining image quality

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements periodic threshold voltage correction by alternating between preparatory driving (which includes correction) and write driving phases. This periodic approach corrects threshold voltage variations at regular intervals rather than continuously, reducing the frequency of high-power correction operations while maintaining sufficient image quality through periodic refreshment of the correction data

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS10977995B2Display unit, driving method, and electronic apparatus

Publication Date: 2021.04.13 SONY GROUP CORP

AI summary

A display unit of the disclosure includes a unit pixel and a driving section that drives the unit pixel. The unit pixel includes a light-emitting device, a capacitor section having a first capacitor and a second capacitor that are coupled in series through a first node, a drive transistor that supplies a drive current corresponding to a potential difference across both ends of the capacitor section to the light-emitting device, and a first transistor that delivers a first voltage to the first node by turning on.