Shift Register Unit for AMOLED Luminance Control

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Solution Overview

Problem

There is a significant deviation between adjusted and desired grayscales in AMOLED display panels, affecting the display effect, necessitating an alternative method to control luminance.

Innovation Solution

A shift register unit and scan driving circuit that adjusts the duration of light emission in OLED displays by synchronizing control signals and voltages, allowing for precise control over the length of time the OLED emits light, thereby adjusting luminance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If data voltage is adjusted to control grayscale, then luminance adjustment is achieved, but large deviation between adjusted and desired grayscale occurs

Engineering Contradiction:

ImproveluminanceVSAvoidgrayscale accuracy

Core Design Contradiction:

Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent changes the control parameter from data voltage to light emission duration. Instead of adjusting the voltage level to control grayscale, the invention controls how long the OLED emits light. This parameter change eliminates the grayscale deviation problem because duration control is more precise and directly correlates with perceived luminance.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the voltage-based electrical control mechanism with a time-based control mechanism. The shift register unit generates control signals that precisely control the timing and duration of light emission, substituting the imprecise voltage adjustment method with a more accurate temporal control approach.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If light emission duration is controlled to adjust luminance, then grayscale accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvegrayscale accuracyVSAvoidcontrol circuit complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the control function into separate modules: the shift register unit generates control signals, the pixel circuit receives and processes these signals, and the OLED executes the light emission. This segmentation allows each module to be optimized independently, managing complexity through functional decomposition.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The shift register unit serves multiple functions: it generates control signals for the pixel circuit, controls the timing of light emission, and manages the overall scanning process. By making this component multi-functional, the patent reduces the need for separate dedicated circuits for each function, thereby managing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10109238B2Shift register unit, driving method thereof, scan driving circuit and display apparatus

Publication Date: 2018.10.23 BOE TECHNOLOGY GROUP CO LTD

AI summary

A shift register unit is disclosed which includes a first control module operable to a) output a signal synchronous with a second clock signal to a second signal output terminal during a duration and to b) generate a first internal control signal, a first output module operable to output a first voltage to a first signal output terminal during the duration in response to the first internal control signal, a second control module operable to generate a second internal control signal, and a second output terminal operable to output a second voltage to the first signal output terminal at an end of the duration in response to the second internal control signal. Also disclosed are a method of driving the shift register unit, a scan driving circuit and a display apparatus.