Display Device Pre-emphasis Voltage for Color Linearity

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Solution Overview

Problem

High-resolution display devices face challenges in maintaining linearity of color coordinates due to insufficient data charge time, especially when switching between different screen modes, leading to potential distortion in white balance and image quality.

Innovation Solution

A method is introduced where a pre-emphasis voltage is applied temporarily to data lines, based on pre-emphasis values calculated using lookup tables specific to each screen mode, to ensure proper charging and discharging of data signals, thereby maintaining linearity of color coordinates across various screen modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If resolution is increased and panel size is enlarged, then display quality is improved, but data charge time becomes insufficient leading to voltage not reaching target level

Engineering Contradiction:

Improvedisplay qualityVSAvoiddata charge time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies pre-emphasis voltage before the actual data voltage to pre-charge the data lines. This preliminary action compensates for the RC time constant delay, ensuring that the pixel reaches the target voltage level within the available scan time despite increased resolution and panel size.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent dynamically adjusts the pre-emphasis voltage level based on the data voltage level being transmitted. Different pre-emphasis values are applied depending on the grayscale level, optimizing the charging process for each specific voltage transition requirement.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If screen mode is changed with different target color coordinates, then display adaptability is improved, but linearity of color coordinate may be distorted

Engineering Contradiction:

Improvescreen mode adaptabilityVSAvoidlinearity of color coordinate

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent applies different pre-emphasis compensation values for different screen modes and different grayscale levels. Each screen mode has its own optimized pre-emphasis lookup table that accounts for the specific color coordinate requirements and timing characteristics of that mode.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses pre-calculated lookup tables that were generated based on measured timing characteristics and color coordinate data for each screen mode. This feedback from measurement to optimization ensures that the pre-emphasis values are precisely tuned to maintain color linearity in each specific operating mode.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11423848B2Display device and method of operating the same

Publication Date: 2022.08.23 SAMSUNG DISPLAY CO LTD

AI summary

A display device comprises a timing controller which provides data comprising a pre-emphasis value and an image data value, and a data driver which supplies to data lines a pre-emphasis voltage generated based on the pre-emphasis value during a first period of a horizontal period, and supplies to the data lines a data voltage generated based on the image data value during a second period of the horizontal period. The timing controller provides data based on which the pre-emphasis value is changed in correspondence with one screen mode selected from a plurality of screen modes having different target color coordinates.