Organic EL Display Power Control Circuit Segmentation

Solution Overview

Problem

Existing organic EL display devices face challenges in reducing the number of wiring lines and circuit size while maintaining effective compensation for threshold voltage variations and power consumption, particularly due to the need for high current capability in power control circuits.

Innovation Solution

A current-driven display device configuration with a power control circuit that applies initialization potentials to common power lines, reducing the number of elements and output buffers, and utilizing a single or multiple common power lines connected to multiple power lines, along with a drive circuit that controls pixel circuits on a row basis for threshold detection, writing, and light emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the power line DSL is driven in conjunction with a control line WSL to provide initialization potential from the power line, then the number of elements in pixel circuit can be reduced, but the circuit size and power consumption of the power control circuit increase due to requiring high current capability output buffers

Engineering Contradiction:

Improvenumber of elements in pixel circuitVSAvoidpower consumption of power control circuit

Core Design Contradiction:

Device complexityVSUse of energy by stationary object

Solution Approach 1:

The pixel circuit is divided into multiple transistor components (first transistor, second transistor, third transistor, fourth transistor) that work together to provide initialization potential from the power line. This segmentation allows the power control circuit to supply initialization potential through the power line without requiring high current capability output buffers, as each transistor controls the potential distribution independently.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The light emission control transistor acts as an intermediary between the power line and the pixel circuit components. It controls when the initialization potential is applied to the anode terminal of the organic EL element, allowing the power control circuit to operate at lower current levels while still achieving effective initialization.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If the power line DSL is driven in conjunction with a control line WSL to provide initialization potential from the power line, then the number of elements in pixel circuit can be reduced, but the circuit size of the power control circuit increases

Engineering Contradiction:

Improvenumber of elements in pixel circuitVSAvoidcircuit size of power control circuit

Core Design Contradiction:

Device complexityVSArea of stationary object

Solution Approach 1:

The pixel circuit is divided into multiple transistor components (first transistor, second transistor, third transistor, fourth transistor) that work together to provide initialization potential from the power line. This segmentation allows the power control circuit to supply initialization potential through the power line without requiring high current capability output buffers, as each transistor controls the potential distribution independently.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The light emission control transistor acts as an intermediary between the power line and the pixel circuit components. It controls when the initialization potential is applied to the anode terminal of the organic EL element, allowing the power control circuit to operate at lower current levels while still achieving effective initialization.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If multiple control lines are connected to each pixel circuit for threshold voltage compensation, then compensation performance is improved, but the number of wiring lines increases making the circuit more complex

Engineering Contradiction:

Improvethreshold voltage compensation performanceVSAvoidnumber of wiring lines

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The power line is designed to serve multiple functions: it provides both the initialization potential and the power supply potential to the pixel circuit. By making the power line multi-functional, the patent eliminates the need for separate control lines that would otherwise be required for initialization, thereby maintaining compensation performance while reducing wiring complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system dynamically switches between different operational modes by controlling the light emission control transistor. During initialization, the power line provides initialization potential; during normal operation, it provides power supply potential. This dynamic operation allows a single power line to replace multiple static control lines.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9361826B2Display device and drive method therefor

Publication Date: 2016.06.07 SHARP KK

AI summary

A display device 100 includes a plurality of pixel circuits 10 arranged two-dimensionally; a plurality of power lines VPi provided for respective rows of the pixel circuits 10; p common power lines 9, each connected to two or more power lines VPi; and a power control circuit 4. Each pixel circuit 10 includes an organic EL element, a plurality of TFTs, and a capacitor and receives an initialization potential from a corresponding power line VPi. The power control circuit 4applies a power supply potential and the initialization potential to the p common power lines 9 in a switching manner. Accordingly, a display device is provided that has a configuration in which an initialization potential is provided to pixel circuits from power lines and that has a power control circuit small in circuit size.