Display Panel Gamma Voltage Compensation for Luminance Uniformity

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Solution Overview

Problem

Display devices experience luminance differences between areas due to varying write times for data voltage and increased current leakage through switching transistors, especially in variable frequency driving.

Innovation Solution

A display device with a driving controller that calculates area-specific correction values using black data voltage information, adjusts gamma reference voltages, and controls data drivers to minimize luminance differences by remapping voltage relationships and adjusting gate and source voltages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If variable frequency driving is implemented to support different refresh rates, then adaptability is improved, but luminance uniformity deteriorates due to varying write times and increased current leakage

Engineering Contradiction:

Improvedriving frequency adaptabilityVSAvoidluminance uniformity

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent divides the display panel into multiple areas (first area and second area) and applies different black data voltage correction values to each area. This local quality approach addresses the luminance uniformity issue by treating different regions with distinct compensation parameters, thereby resolving the contradiction between maintaining luminance consistency and supporting variable frequency driving across the entire panel.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent dynamically adjusts the black data voltage parameter based on driving frequency, dimming level, and temperature conditions. By changing this critical voltage parameter in response to operating conditions, the system maintains luminance uniformity across different refresh rates, effectively resolving the contradiction between adaptability and luminance stability.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If data writing time is extended to accommodate lower refresh rates, then adaptability is improved, but current leakage through switching transistors increases causing luminance differences

Engineering Contradiction:

Improverefresh rate flexibilityVSAvoidcurrent leakage

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent adjusts the black data voltage parameter dynamically based on driving frequency, dimming level, and temperature. By changing this voltage parameter in response to operating conditions, the system compensates for increased current leakage during extended write periods at lower refresh rates, thereby maintaining luminance uniformity while supporting variable frequency operation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements a feedback mechanism where the system measures actual luminance characteristics under different operating conditions and uses this information to calculate appropriate correction values. This feedback loop enables the system to adapt to varying current leakage conditions at different refresh rates, resolving the contradiction between refresh rate flexibility and energy loss.

Inventive Principle:

Principle #23Feedback

3Stability of the object's composition

If black data voltage is adjusted to compensate for current leakage, then luminance uniformity is improved, but device complexity increases due to area-specific correction calculations

Engineering Contradiction:

Improveluminance uniformityVSAvoidcontrol circuit complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent pre-calculates and stores black data voltage information and correction values for different areas under various operating conditions before actual display operation. This preliminary action approach allows the system to quickly retrieve and apply appropriate correction values without performing complex real-time calculations, thereby maintaining luminance uniformity while minimizing the complexity of the control circuit.

Inventive Principle:

Principle #10Preliminary action

4Stability of the object's composition

If area-specific correction values are calculated and applied, then luminance uniformity is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improveluminance uniformityVSAvoidvoltage mapping precision

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent uses software-based parameter adjustment to compensate for manufacturing variations. By dynamically changing the black data voltage parameter based on measured luminance characteristics and pre-calculated correction values, the system achieves luminance uniformity without requiring extremely tight manufacturing tolerances, thereby reducing the stringency of manufacturing precision requirements.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250384856A1Display device, manufcturing method thereof, driving method thereof, and elecronic device using the display device

Publication Date: 2025.12.18 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes a display panel including sub-pixels, a data driver for providing the sub-pixels with a data voltage generated using a gamma reference voltage, a driving controller for controlling the data driver, and a memory storage for providing the driving controller with black data voltage information of a first area of the display panel according to a driving frequency, a dimming level, and a temperature of the display panel.