Gamma Standard Voltage Circuit for Display Driving

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Solution Overview

Problem

In display devices like OLEDs, variations in driving voltage can cause mismatched gamma driving voltage, leading to display issues such as color shift and brightness differences, as existing gamma standard voltage systems fail to compensate effectively for significant changes in driving voltage, resulting in a vicious circle of abnormal compensation.

Innovation Solution

A gamma standard voltage generating circuit that includes a constant voltage element, a following voltage element, and a selecting element controlled by a comparison element to output either the following voltage or constant voltage based on a preset standard, ensuring the gamma standard voltage adapts to driving voltage changes and prevents unlimited compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the gamma standard voltage system uses a fixed voltage reference, then the circuit structure is simple, but the gamma driving voltage becomes mismatched when driving voltage varies significantly

Engineering Contradiction:

Improvecircuit structureVSAvoidgamma driving voltage matching

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent transforms the fixed voltage reference into a dynamic system by introducing a switching element that can select between a constant voltage output and a following voltage output. The following voltage element dynamically tracks the driving voltage changes, while the switching element enables the system to adapt its reference voltage based on the magnitude of driving voltage variation, thus resolving the contradiction between circuit simplicity and voltage matching reliability

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of the voltage reference from fixed to variable by incorporating a following voltage element that generates a voltage tracking the driving voltage. A comparison element detects when the following voltage deviates from the constant voltage by exceeding a threshold, triggering a switch in the reference voltage parameter to maintain gamma driving voltage accuracy under varying driving conditions

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the gamma standard voltage follows driving voltage changes continuously, then the gamma driving voltage adapts to driving voltage fluctuations, but unlimited compensation occurs causing display abnormalities

Engineering Contradiction:

Improvegamma driving voltage adaptationVSAvoiddisplay abnormalities

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback mechanism where the comparison element continuously monitors the difference between the following voltage and constant voltage. When the following voltage deviates beyond a preset threshold from the constant voltage, the comparison element triggers the switching element to stop following and switch to constant voltage output, preventing unlimited compensation and the resulting display abnormalities

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent prepares a constant voltage reference in advance as a safety backup. When the following voltage tracking mechanism detects that it is approaching dangerous deviation levels (exceeding the threshold), the switching element preemptively switches to the constant voltage reference, cushioning against potential display abnormalities before they occur

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Adaptability or versatility

If a switching mechanism is added to select between constant voltage and following voltage, then the gamma standard voltage can adapt to driving voltage changes, but the device complexity increases

Engineering Contradiction:

Improvevoltage adaptation capabilityVSAvoidcircuit structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the constant voltage reference path and the following voltage tracking path into a single unified gamma standard voltage output through the switching element. This consolidation allows the system to adapt to driving voltage changes while maintaining relatively simple circuit structure by sharing common components and using a single switching point to select between the two voltage sources

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11955068B2Gamma standard voltage generating circuit, gamma driving voltage generating circuit and display device

Publication Date: 2024.04.09 BOE TECHNOLOGY GROUP CO LTD

AI summary

Embodiments of the present disclosure provide a gamma standard voltage generating circuit, a gamma driving voltage generating circuit and a display device. The gamma standard voltage generating circuit includes: a constant voltage element for outputting a constant voltage; a following voltage element coupled to a driving voltage terminal, for outputting a following voltage changing with a driving voltage of the driving voltage terminal; a selecting element electrically coupled to the constant voltage element and the following voltage element, for outputting the following voltage 10 or the constant voltage as an output voltage; a comparison element electrically coupled to the selecting element, for controlling the selecting element to output the following voltage when the output voltage meets a preset standard, and controlling the selecting element to output the constant voltage when the output voltage does not meet the preset standard; the constant voltage does not meet the preset standard.