AMOLED Pixel Circuit Driving Method Using Duty Cycle Control

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Solution Overview

Problem

The existing methods for adjusting display brightness in AMOLED displays require numerous lookup steps and additional storage, leading to increased production costs and potential impacts on image fineness due to reduced grayscale adjustments.

Innovation Solution

A driving method for a pixel circuit that uses a pulse signal with a duty cycle to control the luminescence time of a light-emitting device, eliminating the need for lookup table steps and reducing storage requirements, while maintaining the full range of grayscale adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If brightness adjustment is achieved by converting grayscale value to brightness value through lookup table and Gamma curve, then brightness adjustment function is realized, but number of storages increases and FPGA resources are consumed

Engineering Contradiction:

Improvebrightness adjustment functionVSAvoidnumber of storages

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent changes the parameter representation from grayscale value to duty cycle. Instead of storing and converting grayscale values through lookup tables and Gamma curves, the system directly uses duty cycle values to control the light-emitting device's luminescence time. This parameter transformation eliminates the need for extensive storage resources while maintaining brightness adjustment capability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent extracts the brightness adjustment function from the complex grayscale conversion process. By separating the brightness control mechanism and implementing it through duty cycle modulation of the light-emitting device, the system removes the need for lookup tables and Gamma curve calculations, thereby reducing storage requirements.

Inventive Principle:

Principle #2Taking out (Extraction)

2Adaptability or versatility

If brightness adjustment is achieved by converting adjusted brightness value to grayscale value through lookup table, then brightness adjustment is realized, but production cost increases due to numerous lookup steps

Engineering Contradiction:

Improvebrightness adjustmentVSAvoidproduction cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent changes the control parameter from grayscale value to duty cycle. This parameter change simplifies the manufacturing process by eliminating complex lookup table operations and Gamma curve conversions, thereby reducing production costs while maintaining brightness adjustment functionality.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical-like lookup table and conversion process with a more efficient duty cycle-based control mechanism. This substitution simplifies the system architecture and reduces the computational and storage resources required during manufacturing and operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If brightness adjustment is achieved by reducing grayscale range, then brightness control is realized, but display image fineness is degraded

Engineering Contradiction:

Improvebrightness controlVSAvoiddisplay image fineness

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent changes the control approach from reducing grayscale range to using duty cycle modulation. This allows brightness adjustment without compromising the original grayscale range, thereby maintaining display image fineness while achieving effective brightness control through temporal modulation of the light-emitting device.

Inventive Principle:

Principle #35Parameter changes

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

This approach reduces the number of storage resources needed and avoids degrading the display image quality by maintaining the full range of grayscale adjustments, thus lowering production costs and ensuring image fineness.

Implementation Method 1

determining a duty cycle of a pulse signal according to the brightness information; inputting a high level to the first voltage terminal, and inputting a pulse signal with the duty cycle to the gate of the first switching transistor

Methodology Applied

Scientific EffectPulse Width Modulation: Phase Modulation

Implementation Method 2

control luminescence time of the light-emitting device

Methodology Applied

Scientific EffectLuminescence: Luminescence

Data Source

PatentUS9881554B2Driving method of pixel circuit and driving device thereof

Publication Date: 2018.01.30 BOE TECHNOLOGY GROUP CO LTD

AI summary

Embodiments of the present disclosure relate to a technical field of display technology, and provide a driving method for a pixel circuit and a driving device thereof. A problem of cost increase can be solved which is caused by an increase in a number of storages when adjustment is made by way of Gamma curve and table lookup, by means of the technical solutions according to embodiments of the present disclosure. The driving method of the pixel circuit includes acquiring brightness information of a display screen in a light-emitting phase (S101); determining a duty cycle of a pulse signal according to the brightness information (S102); inputting a high level to the first voltage terminal, and inputting the pulse signal with the duty cycle to a gate of the first switching transistor by the first gate line (S103).